a gli~ l~~ S.IrYll 
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DOE/ER-0735

Summaries of FY 1997

Engineering Research

September 1998

U.S. Department of Energy

Office of Energy Research

Office of Basic Energy Sciences

Division of Engineering and Geosciences

Washington, DC 20585

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Foreword

This report documents the Basic Energy Sciences (BES) Engineering Research

Program for fiscal year 1997; it provides a summary for each of the program projects

in addition to a brief program overview. The report is intended to provide staff of

Congressional committees, other executive departments, and other DOE offices with

substantive program information so as to facilitate governmental overview and

coordination of Federal research programs. Of equal importance, its availability

facilitates communication of program information to interested research engineers and

scientists. Each BES Division administers basic, mission oriented research programs

in the area indicated by its title. The BES Engineering Research Program is one such

program; it is administered by the Engineering and Geosciences Division of BES.

Dr. Robert E. Price is technical manager of the Engineering Research Program;

inquiries concerning the program may be addressed to him, in writing, by phone

at (301) 903-5822 / (301) 903-3565 or by fax at (301) 903-0271 (additional

information and updates are accessible on World Wide Web, http://er.doe.gov).

In preparing this report we asked the principal investigators to submit summaries for

their projects that were specifically applicable to fiscal year 1997. The summaries

received have been edited if necessary, but the press for timely publication made it

impractical to have the investigators review and approve the revised summaries prior

to publication. For more information about a given project, it is suggested that the

investigators be contacted directly.

Engineering Research 1997
Introduction

The individual project summaries follow the program overview. The summaries are

ordered alphabetically by name of institution; the table of contents lists all the

institutions at which projects were sponsored in fiscal year 1997.

Each project entry begins with an institutional-departmental heading. The names of

investigators are listed immediately below the title. The funding level for fiscal year

1997 appears to the right of address. The summary description of the project

completes the entry. A separate index of Principal Investigators includes phone

number, fax number and e-mail address, where available.

Engineering Research 1997
Program Review

BES Engineering Research

The BES Engineering Research Program is one of the component research programs

which collectively constitute the DOE Basic Energy Sciences Program. The DOE Basic

Energy Sciences program supports energy related research in the physical and

biological sciences, and in engineering. The chief purpose of the DOE Basic Energy

Sciences Program is to provide the fundamental scientific base on which identification

and development of future, national energy options will depend. The major product of

the program becomes part of the body of data and knowledge upon which the applied

energy technologies are founded; the product is knowledge relevant to energy

exploration, production, conversion and use.

The BES Engineering Research Program was started in 1979 to help resolve the

numerous serious engineering issues arising from efforts to meet U.S. energy needs.

The program supports fundamental research on broad, generic topics in energy related

engineering topics not as narrowly scoped as those addressed by the shorter term

engineering research projects sponsored by the various DOE technology programs.

Special emphasis is placed on projects which, if successfully concluded, will benefit

more than one energy technology. During the first year several workshops were

sponsored for the purpose of identifying energy related engineering research needs

and initial priorities. Representatives from industry, academic institutions, national

laboratories, and leading members of professional organizations (Engineering Societies

Commission of Energy, American Society of Mechanical Engineers, Society of

Automotive Engineers, and Joint Automation and Control Committee) participated in the

workshops. In addition to the participants in the workshops, staff representatives from

the DOE technology programs and other leading U.S. energy engineering experts made

significant contributions to the setting of program priorities. There resulted from this

process a strong confirmation of the need for a long range, fundamental engineering

research program with two major goals. The broad goals that were established by this

process for the BES Engineering Research Program are:

1) To extend the body of knowledge underlying current engineering practice so as to

create new options for enhancing energy savings and production, for prolonging useful

equipment life, and for reducing costs without degradation of industrial production and

performance quality; and

2) To broaden the technical and conceptual base for solving future engineering

problems in the energy technologies.

Engineering Research 1997 Engineering Research 1997
In this process, it was further established that to achieve these goals, the BES

Engineering Research Program should address the following topics identified as

essential to the progress of many energy technologies:

1) Advanced Industrial Technology: improvement of energy conversion and utilization,

opening new technological possibilities, and improvement of energy systems.

2) Fluid Dynamics and Thermal Processes: broadening of understanding of heat

transfer in nonsteady flows, methodology for reducing vibrations and noise in heat

exchangers, and engineering aspects of combustion.

3) Solid Mechanics: continuum mechanics, fracture mechanics, thermomechanical

behavior in severe environments, aging and lifetime reliability of structures.

4) Dynamics and Control of Processes and Systems: development and use of

information describing system behavior (system models), performance criteria, and

theories of control optimization to achieve the best possible system performance

subject to known constraints.

A Scoping Workshop held in December 1985 confirmed the continued needs for

research in these topical areas. Because of budgetary limitations, the implemented

BES Engineering Research Program is somewhat less broad than the program

envisioned above. At present, equal emphasis is being placed in three carefully

selected, high priority research areas; namely,

1) Mechanical Sciences including fluid mechanics heat transfer, and solid mechanics,

but excluding purely computational efforts.

2) System Sciences including process control, instrumentation, and intelligent systems.

3) Engineering Analysis including nonlinear dynamics, data bases for thermophysical

properties of fluids, modeling of combustion processes for engineering application, and

foundations of bioprocessing of fuels and energy related wastes.

These areas contain the most critical elements of the four topics enumerated above;

as such they are of importance to energy technologies both in the short and long term,

and therefore of immediate programmatic interest. It should be noted that other areas

of basic research important to engineering are monitored elsewhere in BES. For

instance, separation sciences and research on thermophysical properties are among

the responsibilities of the Chemical Sciences Division, while microscopic aspects of

fracture mechanics are in the domain of the Material Sciences Division. As resources

permit, other high priority areas are being added to the Engineering Research

Engineering Research 1997 Engineering Research 1997
Program. Thus, as a result of previous growth in the program budget an important

development took place in the Engineering Research Program: two major

concentrations of research were initiated.

First, a new program was organized at Oak Ridge National Laboratory dealing with

intelligent machines in an unstructured environment. Some resources are available for

coordinated, more narrowly focussed, related, high quality research at universities and

other research centers. All such activities are supported and administered directly by

the Engineering Research Program, but some coordination of efforts with the ORNL

program may prove useful.

Secondly in FY 1985, a collaborative research effort was started between MIT and

Idaho National Engineering Laboratory. The collaboration is in two distinct areas:

Automated Welding, and Fracture Mechanics. Collateral, high quality research efforts

at other institutions, including Plasma Process Engineering are supported by the

Engineering Research Program.

In the expectation of a future modest growth of this Program, three International

Workshops on Two Phase Flow Fundamental were held one in September 1985 and

the other in March 1987. The meetings were used to identify basic research needs in

the field of two phase flow and heat transfer; summary reports of the workshops are

available from the Program Office. The proceedings of the two workshops have been

published as volumes in the series "Advances in Heat and Mass Transfer" (Hemisphere

Publishing Company). A third international workshop held in June 1992 surveyed the

status of the field. The proceedings have been published by CRC Publishing

Company, also in the series "Advances in Heat and Mass Transfer".

Two additional workshops were held during 1988. The first dealt with possible research

opportunities in the field of novel devices using the new high temperature

superconductors. The second addressed research needs for bioprocessing of fuels

and energy related wastes. Reports of both workshops have been published.

Additional funds had been provided in FY 1992 to initiate research in the above

mentioned bioprocessing area. Of interest are relevant studies at the intersection of

biology, biochemistry, and chemical engineering.

Another workshop aimed at identifying research opportunities to mitigate the effects of

aging in energy production and distribution systems took place in October i992. The

proceedings have appeared in Applied Mechanics Reviews.

During the past year, workshops have been planned to examine engineering research

in the areas of micro- and nano-meter systems. It is expected to result in an increase

in research in micro- and nano-meter systems.

Engineering Engineering Research 1997
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Research projects sponsored by the BES Engineering Research Program are currently

underway at universities, private sector laboratories, and DOE national laboratories.

In fiscal year 1997 the program operating funds available for research amounted to

about $15.3 million. The distribution of these funds among various institutions and by

topical area is illustrated on the next page. Project funding levels are mostly in the

range of $50,000 to $150,000 per year. Typical duration of a project is three to four

years, with some projects expected to last as long as ten years or more. The BES

Engineering Research projects stem almost without exception from competitive grant

applications. Applications which anticipate definite results in less than two years are

usually referred to the appropriate DOE technology program for consideration. All

those interested in submitting a proposal are encouraged to discuss their ideas with the

technical program manager prior to submission of a formal proposal. Such discussion

helps to establish whether or not a potential project has a reasonable chance of being

funded. The primary considerations for possible support are the technical quality of the

proposal and the professional standing of the principal investigators and staff. An effort

is made to attract first rate, younger research engineers and energy oriented applied

scientists. A high technical caliber of research is maintained by requiring that the

projects supported have potential for a significant contribution to energy related

engineering science, or for an initial contribution to a new energy relevant technology.

Sponsored projects are selected primarily for their relevance to DOE mission

requirements; the contribution to energy related graduate education is an important

consideration. Thus projects sponsored at universities are essentially limited to

advanced theoretical and experimental studies usually performed by faculty members,

staff research scientists, and doctoral candidates.

Engineering Research 1997
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Table of Contents

University of Alabama .................................. 1

University of Arizona .................................. 1

Battelle Memorial Institute .................... ......... 2

Brown University ...................................... 3

University Of California, Berkeley ......................... 3

University Of California, Los Angeles ...................... 6

University Of California, San Diego ....................... 7

University Of California, Santa Barbara .................... 12

California Institute Of Technology ........................ 13

Carnegie Mellon University ............................. 14

University Of Chicago .................................. 14

Clarkson University ................................... 15

University of Colorado ................................. 15

Cornell University ..................................... 16

Dartmouth College .................................... 17

D uke U niversity ...................................... 18

Florida State University ................................ 18

Georgia Institute of Technology .......................... 19

Idaho National Engineering and Environmental Laboratory ..... 19

University Of Illinois ................................... 23

Johns Hopkins University ............................... 26

Robert H. Kraichnan, Inc ............................... 26

Lawrence Berkeley National Laboratory .................... 27

Lawrence Livermore National Laboratory ................... 27

The Lovelace Institutes ................................ 28

McDermott Technology, Inc ............................. 29

University Of Maryland ........... .. .................. 29

Massachusetts Institute Of Technology .................... 32

University Of M innesota ............... ................ 36

National Academy of Sciences/National Academy of Eng ...... 37

National Aeronautics and Space Administration ............ 39

National Center for Manufacturing Sciences ................ 39

National Institute Of Standards And Technology ........... 40

The City University Of New York, The City College ........... 41

State University of New York ......... ................... 43

Northwestern University ................................ 44

University Of Notre Dame ............................... 47

Oak Ridge National Laboratory .......................... 47

Engineering Research 1997

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Table of Contents (continued)

Oregon State University ................................ 48

Pennsylvania State University ........................... 49

Princeton University ................................... 49

Purdue University ..................................... 50

Rensselaer Polytechnic Institute ......................... 51

R ice U niversity ....................................... 53

University Of Rochester ................................ 53

Rockefeller University .................................. 54

Sandia National Laboratories ................. ......... 55

Science Applications Intl Corp ................. ........ 55

Stanford University .................................... 56

University Of Texas At Austin ............................ 59

Tufts University ............... ............. ........ 60

University of W ashington ............................... 61

W ashington University ................................ 62

W ashington State University ............................ 62

University Of W isconsin ................................ 63

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Engineering Research 1997
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University Of Alabama

Dept of Mathematics $0

Tuscaloosa, AL 35487

Hydrodynamic Instabilities and Coherent Structures

A. Frenkel

The objective of this research is to further the fundamental understanding of stability properties

of several far-from- equilibrium fluid systems which are relevant to energy engineering sciences.

In particular, flows periodic in space and possibly in time are studied as models to gain insights

into such turbulence phenomena as large-scale coherent structures, eddy viscosity, and the

inverse cascade of energy. Film flows--such as core-annular ones--are important to, e.g.,

lubricated pipelining of viscous oils. The large-scale evolution equations for the different systems

may exhibit common features, such as pattern formation and coherent structures.

Some of the results are as follows: A rigorous iterative method was suggested for the problems

of periodic-flow stability. The possibility of negative isotropic large-eddy viscosity was

demonstrated, resolving a rather long-outstanding question. A weakly nonlinear Landau-type

theory was constructed for an intermediate-scale instability of a periodic flow. The spatial

structure of the saturated disturbances of this non-uniform flow is significantly different from

previously known, uniform cases.

For film flows, a perturbative method capable of yielding both the evolution descriptions and the

parametric conditions of their validity was suggested. ighly nonlinear evolution equation of a wavy

flow down a cylinder was obtained. Its numerical simulations yielded an excellent agreement with

experiments. They also revealed, for the first time ever in numerical simulations, irreversible

coalescences of soliton-shaped coherent structures; these are now thought to play an important

role in the wave dynamics of film flows. Also, a theory of a flow down an inclined plane was

constructed. Simulations of the evolution equation showed a remarkable agreement with

three-dimensional wave patterns observed in recent experiments.

Some fundamental questions concerning commonly used perturbative approaches were clarified.

Certain deficiencies of well-known evolution equations were pointed out.

University of Arizona

Aerospace & Mechanical Eng $150,000

Tucson, AZ 85721

Film Cooling in a Pulsating Stream

I. Wygnanski, H. Fasel, A. Ortega

Wall jets have traditionally been used for boundary layer control and in heat transfer applications

such as film-cooling and evaporation enhancement. This summary presents the status of an

investigation that attempts to understand the complexities behind momentum and energy

transport in externally excited wall jet flows. The approach combines experimentation, direct

numerical simulations (DNS) and stability theory. The experimental results for the laminar wall jet

Engineering Research 1997 Engineering Research 1 1997
flowing over a constant temperature surface substantiated the stability theory for both the

streamwise velocity and temperature fields for low excitation levels. For higher forcing levels, the

experimental findings were compared to incompressible DNS which solve the incompressible

Navier Stokes equations in vorticity-velocity formulation in conjunction with the energy equation.

Both experiments and DNS revealed that forcing at high excitation levels causes a significant

reduction in the skin friction and a concomitant increase in heat flux relative to the unforced case.

A significant growth of the sub-harmonic component was also observed within the measurement

domain. It is believed that these large scale and low frequency structures appear to contribute

to the reduction and augmentation of the shear stress and heat flux. Understanding the

complexities of the turbulent wall jet with heat transfer is currently the focus of the research.

Battelle Memorial Institute

Engineering Mechanics Dept $0

Columbus, OH 43201-2693

An Investigation of History-Dependent Damage In Time-Dependent Fracture Mechanics

F. Brust, Jr.

In order to meet the demand imposed by future technology, new plants with increased energy

efficiency must operate at relatively high temperatures. Additionally, the existing power

generation equipment in the United States continues to age and is being used far beyond its

intended life. Some recent failures have clearly demonstrated that the current methods for

insuring safety and reliability of high temperature equipment is inadequate. Owing to these

concerns, a thorough understanding of high temperature failure initiation and propagation in

materials exposed to variable mechanical and thermal loading is very important.

In the past, the evolution of damage has been addressed through a macroscopic theoretical

model (developed as part of this effort) which attempt to predict the crack growth and failure

response of material components exposed to high temperature conditions. However, micromechanical processes such as diffusion of atomic flux into grain boundaries, elastic

accommodation and creep deformation of the material and grain boundary sliding do contribute

significantly to the nucleation and growth of voids leading to failure. Understanding gained by

consideration of micro-mechanics of cavity growth is crucial for developing damage-based

constitutive models as well as methodologies for life prediction of structural components. While

the application of this understanding in estimating life of structural materials experiencing high

temperature creep has met with some success, it is of limited use for structural components

experiencing complex load histories under high temperature conditions.

A micro-mechanical model accounting for rate-controlling microscopic processes has been

developed as part of this effort. To date, both sustained and variable load histories have been

investigated in two-dimensional geometries. The results illustrate the importance of accounting

for nonlinear changes in geometry, grain-boundary diffusion processes, elastic accommodation

of the surrounding material as well as more realistic constitutive laws for creep deformation.

Current efforts involve investigating different load histories and three-dimensional effects. In

addition, the ultimate goal of this effort is to establish a firm connection between the micro- and

macro-mechanical models thereby leading to the development of appropriate methodology for life

prediction of structural components exposed to high temperature conditions involving complex

load histories.

Engineering Research 2 1997 Engineering Research 2 1997
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Brown University

Dept of Chemical Engineering $99,860

Providence, RI 02912

Simulation and Analysis of Dyanmic Failure of Ductile Materials

L.B. Freund

A central goal in the mechanics of materials is the determination of parameters which

characterize macroscopic failure of materials in terms quantifiable characteristics of their

microstructure. The motivation is to establish which characteristics account for macroscopic

failure, with a view toward improvement of failure resistance through material selection or

microstructural design. In the present project, emphasis is on the behavior of ductile structural

alloys under high rate loading conditions. Thus, the dominant mechanism of plastic deformation

is crystallographic slip and material strength degrades through nucleation, growth and

coalescence of micro-voids. Plastic strains in such processes can be large and strain localization

is common. The approach is to adapt methodologies for analysis of elastic-viscoplastic systems

to problems selected on the basis of their relevance to safety of pressure vessel and piping

systems, to materials processing and metal forming technologies, and to structural reliability

under dynamic loading. Initial emphasis has been on failure of an explosively loaded ring

expanding under plane strain conditions, a configurationwhich has been studied experimentally.

Calculations reveal that strain localization sites, or necks, are more pervasive under rapid loading,

and the spacing of necks decreases with increase in loading rate. The influence of inertia on

bifurcation of deformation states is also being investigated theoretically. The project is being

carried out in collaboration with colleagues involved in experimental research on dynamic ductile

failure at the California Institute of Technology.

University Of California/B

Dept of Chemical Engineering $82,867

Berkeley, CA 94720

Enzyme Adsorption and Activity at-tiquid-Liquid Interfaces - H. Blanch

Protein adsorption at oil/water interfaces is the primary phenomenon governing formation of

stabilized protein adsorption, and the kinetics of interfacially active enzymes. We apply pendant

drop tensiometry, total internal reflection fluorescence spectroscopy (TIRFS) and thin film

balance/interferometry to study enzyme adsorption behavior. We have also constructed a reactor

to follow enzyme kinetics at oil/water interfaces. Pendant drop tensiometry has been used to

follow the dynamic interfacial tension of several well characterized proteins at the heptane

interface and hydroxynitrile lyase from Prunus amygdalus at the interface of several different oils.

Transient interfacial tension studies show that at short times (seconds), predicted diffusional

effects are observed. At extended times (hours), adsorbed proteins form gel-like layers.

Adsorption is accompanied by conformational changes and interactions between adjacent

molecules, often resulting in the formation of a quasi-solid macroscopic skin at the interface. As

the nature of the oil is changed from nonpolar to more polar the surface pressure increases

demonstrating higher adsorption and greater enzyme denaturation. We have observed that the

increased denaturation correlates more closely with oil/water interfacial tensions than with

Engineering Research 3 1997 Engineering Research 3 1997
solubility's. The effect of oil on enzyme interfacial activity will be examined using the reactor

described above. We also use fluorescence spectroscopy to follow protein adsorption and to gain

information on protein molecular conformation in the adsorbed state. A novel TIRFS for

liquid/liquid interfaces has been developed in our lab. The apparatus enables the dynamics of

protein adsorption to be followed while also giving us a means to test the reversibility of surface

reactions in a non-invasive manner. Studies have shown a fluorescein-beta-casein conjugate

irreversibly adsorbs at the oil/water interface after long term exposure. At early times we have

observed exchange between native, adsorbed b-casein and bulk fluorescein-beta-casein

conjugate. The ability to exchange decreases with continued exposure of the adsorbed protein

to the interface. Native and thermally denatured proteins have been studied using the thin film

balance. The denatured protein stabilized a thicker film than the native protein at a given

concentration demonstrating the expanded conformation of the denatured protein.

University Of California/B

Dept of Mechanical Engineering $134,231

Berkeley, CA 94720

Ultrashort Laser Heating anad nase Change in Liquids

C.-L. Tien, C. P. Grigoropoulos

The general objective of this research program is to achieve a better understanding of laser-liquid

interactions from the thermal perspective. Two main tasks were proposed for investigation: the

fundamental mechanisms of high-intensity, short-pulse laser heating of liquids and

pulsed-laser-induced vapor-phase nucleation and growth. This report presents the progress of

the research for these two tasks.

Mechanisms of High-Intensity Laser Heating of Liquids

Residual moisture is a problem in microelectronics and microelectromechanical systems (MEMS)

devices which can result in corrosion, device degradation, and even complete device failure.

Traditional methods of removing liquids are often not viable due to constraints on the maximum

allowable temperature or may not remove all of the liquid. In addition to thermal heating,

ultrashort-pulse lasers can remove undesirable surface species through an electronic desorption

mechanism. When the laser pulse duration is shorter than the relaxation time of the material,

typically on the order of 1 picosecond (10-12 s), non-equilibrium heating of the energy carriers and

the lattice results making electronic desorption possible.

Electronic desorption from metal and semiconductor surfaces due to short-pulse laser heating

has been analytically and computationally modeled. For metal substrates, regimes of thermal and

electronic desorption were identified along with characteristic length and time scales. A feasibility

experiment demonstrating *hl recovery of microstructures which stuck to the underlying substrate

due to stiction was conducted. Stiction is the permanent adnesion of one part of a microstructure

to another and the capillary forces generated by the drying rinse liquids play a major role in its

occurrence.

Engineering Research 4 1997

Engineering Research 4 1997
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Pulsed Laser-Induced Phase-Change and Ablation in Absorbing Liquids

The phase-change process and the generation of acoustic transients in the pulsed laser-induced

ablation of absorbing liquids were investigated [1]. Aqueous solutions having different absorption

coefficients were irradiated by a nanosecond pulsed laser. The ablation process including the

vapor cavity formation and the acoustic-wave propagation were visualized by laser flash

photography. The generated pressure transients were measured using a broadband piezoelectric

pressure transducer. Simultaneous optical transmission detection was also carried out in order

to elucidate the vapor-phase kinetics and determine the ablation threshold. The effects of the

liquid absorption on the ablation mechanism and the acoustic-pulse generation were investigated.

The results showed that the ablation is initiated by cavitation driven by the tensile component of

the produced thermoelastic stress. The ablation threshold corresponds to peak surface

temperatures that are substantially below the saturation temperature at the ambient pressure.

Three distinct stages were identified in the ablation process: the initial stage with negligible

surface deformation and with ejection of a small amount of vapor, the second stage with violent

vapor plume and bulk liquid jet ejection that is accompanied by significant surface deformation,

and the final stage of large scale hydrodynamic motion. The pressure transient is generated

thermoelastically at low laser fluences, but the contribution of the recoil momentum exerted by

the ablation plume becomes dominant at high laser fluences.

The interaction of pulsed laser radiation of hundreds of microseconds duration with bulk liquids

was examined. For these slower heat input rates, the phase-change process occurs thermally.

In the free boundary case, the ablation threshold is marked at peak temperatures near the

saturation temperature. A surface tension driven hydrodynamic instability inhibits the growth of

the vapor phase, leading to cavity collapse and generation of acoustic pressure in the liquid. In

the presence of a rigid boundary, the violent collapse of the formed bubble is accompanied by the

release of a strong pressure pulse into the liquid.

Pulsed-Laser-Induced Vapor-Phase Nucleation and Growth

Irradiation of a KrF excimer laser beam of nanosecond pulse duration on an absorbing solid

surface immersed in a transparent liquid induces rapid thermal expansion and explosive

vaporization of the liquid accompanied by pressure pulse generation. The pressure contribution

due to the thermal expansion of the solid sample and bubble formation was measured by the

probe beam deflection method as well as by a broadband piezoelectric transducer. The pressure

generation is enhanced by the bubble expansion in the superheated water for laser fluences

exceeding the bubble nucleation threshold. The bubble growth dynamics was examined by a

novel, non-contact optical interference technique. This work quantified, for the first time, the

transient behavior and growth rate of a submicron thick bubble layer in the nanosecond time

scale. Experiments are now focused on the study of pulsed laser-induced cavitation and phasechange in absorbing liquids.

Engineering Research 5 1997
University Of California/LA

Mech, Aero & Nuclear Eng Dept $140,712

School of Eng & Applied Science

Los Angeles, CA 90024-1597

Basic Studies of Transport Processes in Porous Media

1. Catton

The objective of this project is to develop an understanding of the governing physical processes

at a level appropriate for development of macroscopic models for use in the analysis of

engineered energy systems. Current work considers both single-and two-phase flows. Efforts are

both theoretical (numerical in some cases) and experimental. Emphasis is placed upon the

development of mathematical models for single-and two-phase turbulent transport in highly

porous media with regular, non-uniform, isotropic and non-isotropic characteristics. The basis of

the work is a hierarchical heterogeneous volume averaging theory (VAT) using fully turbulent

models with Reynolds stresses and fluxes in every pore space building from the lowest level.

Boundary and interface conditions are incorporated at various scales leading to descriptions of

momentum, heat and mass transport in porous media.

The VAT equations for developed flow and diffusive processes in a random, highly porous

medium have been developed along with the statistical and numerical methodology needed to

treat the fluctuation terms for various assigned random porous morphologies. Models have been

developed to describe turbulent flow, diffusion of admixtures, and energy processes in highly

porous media. Using second order turbulent models, equation sets have been obtained for

laminar and turbulent filtration and two-temperature or two-concentration diffusion in non-isotropic

porous media and interface exchange and micro-roughness. The equations differ from those

found in the literature. We continue to work on closure problems that arise in their

implementation.

In the search for closure it was shown that terms in the stationary integro-differential heat-and

mass transport equations based on VAT that are normally ignored, must be kept if the medium

morphology characteristics are spatially dependent. It was also found that polymorphism of the

near surface fluid layers in fine pores cause differences in the bulk liquid viscosity leading to

inapplicability of the Darcy law.

The transport equations needed to model fluid-media interface pressure and heat resistance

losses and the heterogeneity of the medium morphology have been developed to correct pressure

loss experimental results separating the bulk pressure drop from the inlet and outlet losses. A

method of normalization of data from various porous media measurements was developed from

the VAT based equations and shown collapse many of the correlations developed from the

Reynolds-Forchheimer type of equation.

Diode Array Velocimetry (DAV) and a new method of data analysis have been used to obtain the

turbulent characteristics of flow in a pipe and they compare well to the results of other methods.

This method will be used to study the impact of various regular surfaces on the turbulent structure

of the flow to obtain data needed for closure of the VAT based equations. Experimental

measurements of the Fanning friction factor for foamed ceramics and metals are nearing

completion. Heat transfer measurements will soon begin.

e r

Engineering Research 6 1997
University Of CalifornialLA

Physics Dept $77,000

Los Angeles, CA 90024

Nonlinear Waves in Continuous Media: Application to Stochasticity and Energy

Concentration

S. Putterman

We propose to study the effects of nonlinear interactions on the fate of energy that is injected into

a continuous medium so as to drive it far off-equilibrium. In some cases nonlinear processes lead

to a spectacular concentration of energy such as is apparent in sonoluminescence; the

transduction of sound into light. This phenomenon will be studied with the goal of understanding

the light emitting mechanism and the underlying bifurcations which control its parameter space.

An attempt will be made to define and locate a parallel phenomena in crack motion and

triboelectrification. Nonlinearity can also lead to the randomization of energy as evidenced by the

stochastic properties of turbulence. In this direction we propose to study turbulently interacting

capillary waves. We will investigate collective modes of turbulence and the development of

correlations on ultra-long time scales. Finally, with regard to the appearance of structure in

nonlinear systems, we will search for higher dimensional solitons. These structures resist

diffraction as well as dispersion.

University of California/SD

Scripps Inst of Oceanography $75,000

La Jolla, CA 92093-0402

Broadband Signals: Signal Processing in Chaos

H. Abarbanel

The analysis of chaotic signals observed in measurements on physical systems is of importance

in energy problems ranging from fluidized bed flows in fossil energy applications to determination

of the natural climate variability to the uncovering of simple models for complex behavior in fluid

flows. This research has developed tools for this analysis which allows one to reconstruct the

multivariate state space of a system from observations, time lagged, of a single dynamical

variable. The time delay, the dimension, and properties of the strange attractor can all be

determined from these data. The concept of unfolding the attractor using the method of global

false nearest neighbors and then determining locally the number of dynamical degrees of freedom

using the local version of this has brought to the study of complex behavior a robustness which

allows it to be used in engineering analysis and design. The algorithms developed for this

purpose have also been used in a variety of applications requiring the separation of a chaotic

signal from another information bearing signal or 'noise'; The tool kit of these algorithms is being

ported to a common interface for use in the energy related sciences.

Engineering Research 7 1997
University Of California/SD

Dept of Chemistry, 0340 $104,612

La Jolla, CA 92093

Noisy Nonlinear Systems

K. Lindenberg

The broad objective of this project is to investigate the interplay of nonlinear deterministic

dynamics with spatial and temporal fluctuations.

Work has continued on coupled anharmonicnonlinear arrays. In soft anharmonic classical arrays

at finite temperatures theentropy-driven energy localization mechanism called stochastic

localization has been probed by comparing the transition rates of bistable impurities embedded

in a chain of soft oscillators with those in a harmonic chain. The differences can be dramatic.

In quantum systems at zero temperature it is shown that ubiquitous semiclassical models are not

consistent with the behavior obtained for the stationary states of the system via new and highly

accurate variational results.

The directed motion of a particle in a periodic non-symmetric ratchet potential driven by

symmetric time-correlated forces has been investigated. An expression for the induced current

at large correlation times that correctly captures the qualitative features of the ratchet motion has

been derived. Color-induced current reversal of a rigid dimer moving in a ratchet has been

demonstrated numerically.

The escape rate of a Brownian particle over a potential barrier is strongly affected by barrier

fluctuations. Such a system can exhibit a maximum in the escape rate as a function of the barrier

fluctuation parameters. An expression for the escape rate that shows this resonant activation has

been derived and has been confirmed quantitatively via numerical simulations.

University Of California/SD

Inst for Nonlinear Science, 0402 $104,285

La Jolla, CA 92093

Structure and Modeling of Turbulence

E. Novikov

Well developed turbulent flows are encountered in many energy engineering enterprises, as well

as in environmental, aerospace and naval engineering. The number of degrees of freedom for

such flows is enormous and direct numerical simulations (DNS) are impossible now and in a

foreseeable future.

One of the major goals of this project is to advance the knowledge of the structure of turbulence,

aiming it at a subgrid-scale modeling for the large-eddy simulations (LES) and at a transformation

from homogeneous to nonhomogeneous turbulent flows. The developed approach for

achievement of this goal includes: conditional averaging of the Navier-Stokes equations (NSE);

use of Markov processes with dependent increments (consistent with NSE); breakdown

coefficients (for a description of intermittency) and associated infinitely divisible probability

distributions.

Engineering Engineening Research 8 8 1997
Among the obtained results are: probability distribution for the three-dimensional (3D) vectors o

velocity increments, which has an unusual form and experimentaiiy observed exponential

asymptotics; a new scaling for experimentally and numerically observed 3D "vortex strings", 2D

coherent vortices and coherent structures of scalar fields; the whole 3D conditionally averaged

vorticity field (with fixed vorticity in one point) and its characteristics, obtained by DNS on the

CM-5 parallel computer, using finite differences on (256) 3 grid; statistical characteristics of

microcirculations in 3D and vorticity increments in 2D; an imbedding of the phenomena of

intermittency and scale similarity into the theory of infinitely divisible probability distributions;

probability distributions and moments of the breakdown coeffcients for the energy dissipation,

compared with experimental data for the Taylor-scale Reynolds number 3200; a hierarchy of

subgrid- scale models, tested by DNS and by LES for isotropic and free-surface turbulence; an

analytical transformation from homogeneous to nonhomogeneous turbulent flows, tested by data

for free-surface turbulence in a presence of a solid boundary; a Markovian body force for a

modeling of solid boundary; distribution of droplets in turbulent spray.

University Of California/SD

Inst for Nonlinear Science $153,000

La Jolla, CA 92093

Spatiotemporal Wave Patterns: Models and Analysis

M. Rabinovich, L. Tsimring

Key phenomena of pattern evolution and spatio-temporal disorder in nonequilibrium media and

complex systems are investigated experimentally and theoretically. We consider the dynamics

of defects against the background of regular two-dimensional patterns (rolls, hexagons,

quasi-crystalline structures); the self-organization of an irregular ensemble of defects and the

formation of domain walls, as well as the interaction of two-dimensional patterns with large-scale

flows. Experiments are carried out with Faraday ripples, Benard-Marangoni convection, and an

oscillating soap film. The experiments with soap film demonstrate that for a given steady flexural

mode pattern, increasing the amplitude of mode oscillation leads to the excitation of the planar

vortices. For large enough amplitude in a square cell, one can see the spatio-temporal chaos. We

proposed a theoretical model based on the wave-boundary interaction of excited Marangoni

waves. The model reveals a vorticity generation mechanism in vibrating soap films. The model

qualitatively reproduces many steady vortex patterns observed in the experiment.

Spatio-temporal patterns in lattice models of the cortex are also addressed. We proposed a

nonlinear dynamical model that is able to translate the temporal information coded by temporal

patterns of spike's sequences into the neuronal activity of distributed processing system and to

store this information. As a result of external stimulation the unstable spatio-homogeneous mode

of the model evolves into the quasistationary mode with complex spatiotemporal dynamics.

We also demonstrated that spatiotemporal patterns from one excitable media can be conveyed

through a small number or channels into another equivalent excitable media.

We proposed a theoretical model for pattern formation in a thin granular layer on a vibrating plate.

This model, in agreement with experiments, exhibits subcritical transition, rolls, squares, and

localized stated - oscillons.

Engineering Research 9 1997
University Of California/SD

Dept of Physics, 0319 $126,731

La Jolla, CA 92093

Experimental Study of 2D Traveling-Wave Patterns in Binary Fluid Convection

C. Surko

This research involves the study of convection in fluid mixtures of ethanol and water. This system

has proven to be a good model for studying nonequilibrium traveling-wave phenomena, and it

also provides insights into other behavior in doubly diffusive systems in which the transport (in

this case, of heat and concentration) occurs on different time scales. As a fluid dynamical

system, the phenomena of interest are closely related to atmospheric and oceanographic flows.

As a model for traveling-wave dynamics, it provides useful insights in understanding physical

systems of practical importance, such as mode control in large-aspect-ratio lasers.

One focus of current work is the study of 2-D traveling wave patterns in a large-aspect-ratio

container. In an effort to characterize these patterns and their evolution, numerical techniques

were developed to identify the phase defects and to calculate their trajectories. The statistics of

the defects provides an accurate measure of the disorder in thepattems. Work in progress

explores the extent to which the motion of the defects can be predicted and used to determine

the evolution of the patterns.

Recently, an instability was discovered when the fluid layer is heated from above -- a situation

which is stable in a pure fluid. A large-wavenumber pattern develops which appears to be closely

related to salt fingering in thermohaline convection. The observed flow patterns exhibit many

interesting characteristics, including a wave number spectrum which evolves in time and

persistent stochastic dynamics.

University Of California/SD

Institute of Nonlinear Science $104,030

La Jolla, CA 92093-0402

Modeling of Process Control

L. Tsimring

Traditionally, for ease of operation and analysis, technological systems (manufacturing systems,

communication systems, etc.) have been designed to behave in as linear a manner as possible.

Increasingly tight specifications, environmental considerations and economic pressures are

pushing the operational windows into regions where assumptions of linearity tend to break down.

This project aims to the development of tools for building nonlinear models for complex temporal

and spatiotemporal systems. These models can be used for system classification, control, and

inter-instrument validation. Our models are based on input/output data and do not require the

knowledge of underlying dynamical equations. Building on this modeling we devised several

control schemes for nonlinear chaotic systems.

Engineering Research 10 1997

Engineering Research 10 1997
U U

One way to control a system is to synchronize it with a known system or a dynamical model. Our

recent work included building models for generalized synchronization between non-identical

systems and developing numerical and experimental tools for detecting it.

We studied the effects of noisy and band-limited channels between coupled chaotic systems on

the quality of synchronization and communication.

We studied numerically and experimentally a new data-based entrainment technique for trajectory

planning of an unknown nonlinear system. This technique allows one to build an input-output

model directly from data and drive the system towards the desired trajectory (not necessarily

periodic) using an accessible control parameter.

University Of California/SD

Dept of App Mech & Eng Sci $146,307

La Jolla, CA 92093-0411

Fundamental Studies of Spray Combustion

F. Williams, P. Libby, S. C. Li

This research, involving both experimental and theoretical components, has addressed droplet

and spray characteristics in counterflowing streams. A test rig which permits a wide variety of

investigations including nonpremixed, premixed and partially premixed systems in both laminar

and turbulent streams represents the main experimental setup. A two-component phase Doppler

particle analyzer (PDPA) is employed to obtain droplet size, number density and two components

of velocity. In addition, in portions of spray flames not containing droplets, measurements are

made of the profiles of temperature and of concentrations of stable species, including the oxides

of nitrogen. Thermocouples and gas choromotography and a nitrogen-oxides analyzer are used

for the measurements. One recent research effort has been concentrated on the reduction in

NOx formation in two-stage flames by water droplets or carbon dioxide. A paper from this

research was presented by S.C. Li at AMSE Turbo Expo '96, June 10-13, 1996, Birmingham, UK

and it was selected the 'Best Technical Paper' by Interational Gas Turbine Institute. A second

effort has been devoted to staged combustion of methanol and other liquid fuels; in this case

reactants are partially premixed to improve the characteristics of spray combustion such as

reducing emissions of oxides of nitrogen and extending the ranges of stable spray combustion.

Three papers from our research on spray combustion have been accepted for publication,

including one invited review paper entitled 'Spray Stagnation Flames' in Progress in Energy and

Combustion Science. One paper, entitled 'NOx Reduction in Diesel-Fuel Flames by Addition of

Water and CO2' will be presented at 1997 Diesel Engine Emissions Reduction Workshop at

UCSD sponsored by DOE. Experimental work on spray turbulent combustion is underway.

Engineering Research 1997

Engineering Research 11
University Of California/SB

Dept of Physics $148,028

Santa Barbara, CA 93106

Bifurcations and Patterns in Nonlinear Dissipative Systems

G. Ahlers, D. Cannell

This project consists of experimental investigations of heat transport, pattern formation, and

bifurcation phenomena in non-linear non-equilibrium fluid-mechanical systems. These issues are

studies in Rayleigh-Benard convection, using both pure and multicomponent fluids. They are of

fundamental scientific interest, but also play an important role in engineering, materials science,

ecology, meteorology, geophysics, and astrophysics. For instance, various forms of convection

are important in such diverse phenomena as crystal growth from a melt with or without impurities,

energy production in solar ponds, flow in the earth's mantle, geo-thermal stratifications, and

various oceanographic and atmospheric phenomena. Our work utilizes computer-enhanced

shadowgraph imaging of flow patterns and high-resolution heat transport measurements.

We studied convection in a gas (CO) under pressure (about 30 bar) with a Prandtl number Pr=1,

in a very large aspect ratio sample (radius/height up to 150). For parameter values where

time-independent parallel straight rolls were theoretically predicted to be stable, we found a state

of spiral-defect chaos (SDC). These experimental results have stimulated a great deal of

theoretical work, using both analytical and numerical methods and various model equations for

convection.

We extended our experiments on SDC to small values of Pr by using mixtures of gases. If one

component of the mixture has a large and the other a small molecular mass, values of Pr as small

as 0.14 can be reached. The first appearance of SDC shifts closer to the onset of convection as

Pr decreases. This gives information about the origin of SDC, but has not yet been explained

quantitatively.

We investigated convection in a nematic liquid crystal in a horizontal magnetic field (H). We found

excelent agreement with recent theoretical predictions for the bifurcation line R-C(H), and for the

convection-roll orientations as a function of H. We also used this system to study convection

when two phases (the nematic and isotropic phases) are present in the cell. Convection in the

presence of a first-order phase change is relevant to convection in the earth's mantle; ours are

the first quantitative experiments relevant to this important problem.

University Of California/SB

Dept of Chemical & Nuc Eng $111,700

Santa Barbara, CA 93106

Wave Turbulence Interactions

S. Banerjee

The work is part of an ongoing research effort aimed at understanding transport processes across

a gas-liquid interface. The research includes both experimental and computational studies

focusing on the effects of waves on turbulence in a liquid stream. Two- and three-dimensional

Engineering Research 12 1997
mechanically generated waves, spanning the range of conditions from sinusoidal waves to

micro-breaking are studied. Experimental work involves using a 3-D LDA synchronized with

ultra-sonic surface position measurements. Flow visualization with micro-bubbles and high speed

video are used for direct examination of flow structures. DPIV technique are further applied to the

flow visualization video images for in-depth quantitative flow field analysis.

Experimental results indicate that the turbulence intensity away from the wall was substantially

increased as a result of the waves, especially close to the interface, which suggests possible

enhancement of interface scalar transport. The increase appears to be a consequence of

turbulence production in the outer flow region due to wave-induced Reynolds stress. Turbulence

intensity in the wall region and turbulence wall structures were not significantly affected.

Wave-induced turbulence was also seen in a laminar flow by flow visualization.

Direct numerical simulation of gas and liquid flowing across a mobile interface is being conducted.

The results will allow more detailed examination of the effects of waves on turbulence production.

California Institute of Technology

Graduate Aeronautical Laboratories $99,904

Pasadena, CA 91125

Dynamic Failure Characterization of Ductile Steels

A. Rosakis

The goal of the current research program is to study dynamic crack initiation in ductile steels (304

Stainless Steel and A 533 B Steel) at different loading rates and to establish appropriate dynamic

fracture criteria. A variety of infrared and visible optical methods and high speed photography are

used in this study. As part of our work we have developed novel experimental methods to achieve

our tasks.

The precracked steel specimens are subjected to dynamic three-point bend loading by impacting

them in a drop weight tower. This impact results in deformation and fracture initiation. During the

dynamic deformation and fracture initiation process the time history of the transient temperature

in the vicinity of the crack tip is recorded experimentally using a high-speed infrared detector. The

dynamic temperature trace in conjunction with the HRR solution is used to determine the time

history of the dynamic J-integral, J(t), and to establish the dynamic fracture initiation toughness,

S'(t)=JYct, where t = to is the time of fracture initiation. The measurements made using highspeed thermography are validated through comparison with determination of J(t) by dynamic

optical measurements of the crack tip opening displacement. Finally, the micromechanisms of

fracture initiation are investigated by studying the fracture surface using scanning electron

microscopy.

Engineering Research 3 1997

Engineering Research 13 1997
Carnegie Mellon University

Chemical Eng Dept $170,000

Pittsburgh, PA 15213

Systematic Process Synthesis and Design Methods for Cost Effective Waste

Minimization

L. Biegler, 1. Grossmann, A. Westerberg

This project is developing a novel integrated approach for process synthesis and design to

address recent environmental challenges. The approach provides rigorous trade-offs among raw

material and energy costs, capital investment and waste treatment. Issues of waste minimization

addressed include:

1. Economic design of reactor networks that minimize conversion of raw materials to waste

byproducts.

2. Synthesis of separation sequences to isolate, redirect and recycle byproducts.

3. Integrated synthesis and design of reaction, separation and energy systems with environmental

and operability concerns, also dealing with process uncertainty.

Reactor designs that are optimized and synthesized simultaneously with the process flowsheet

can have the greatest impact for process improvement, both from an environmental and an

economic perspective. A quantitative targeting approach for reactor networks is permitting the

reduction of waste byproducts at the source. The second task concentrates on the synthesis of

flexible separation processes (displaying azeotropic and liquid/liquid behavior) that can

accomodate variations in the process. Cooperative search methods are being developed to

overcome the combinatorial explosion of alternatives. The third task combines structural

optimization and problem decomposition at various modeling levels in order to screen alternatives

based on economic, environmental and operabilty trade-offs. Novel decomposition methods are

being developed for the synthesis and operation of utility plants that must cope with changes in

demands and waste treatment requirements.

University Of Chicago

The Enrico Fermi Institute $177,633

Chicago, IL 60637

Fundamentals and Techniques of Nonimaging Optics

R. Winston

Nonimaging optics departs from the methods of traditional optical design to develop instead

techniques for maximizing the collecting power of concentrating elements and systems. Designs

which exceed the concentration attainable with focusing techniques by factors of four or more and

approach the theoretical limit are possible. Our theoretical work on nonimaging designs has led

to our group experimentally demonstrating ultra-high flux from sunlight which exceeds previous

results by substantial factors. Our "tailored edge ray" method of nonimaging design has

advantages for many applications both in energy collection and in illumination. Progress on

Engineering Research 14 1997 Engineering Research 14 1997
non-rotationally symmetrical designs has led to potentially important advances in illumination

systems. Our work on generalized radiance and instrument functions has contributed to a better

understanding of the foundations of radiometry.

Clarkson University

Dept of Chemical Engineering $143,423

Potsdam, NY 13699-5705

Surfactant Effects on Mass Transfer for Bubbles at Large Reynolds Numbers

J. McLaughlin, R. J. Nunge

The main objective of this project is to develop a better understanding of mass transfer between

bubbles and impure liquids. New techniques will be developed that can be used to analyze mass

transfer in a broad range of problems. The focus is on bubbles between 0.5mm and 2.0mm in

water. Issues of particular interest are the transient period during which surfactants adsorb onto

the bubble and the effect of the transient on bubble dissolution.

The scientific approach involves laboratory experiments and numerical simulations. Experiments

will be done to measure the velocity and dissolution of bubbles in both pure water and water

containing controlled amounts of surfactants. The numerical simulations will provide information

about the flow and concentration fields around the bubble and the dependence of the transient

period on surfactant sorption kinetics. A new numerical technique will be used to simulate mass

transfer between a bubble and the surrounding liquid.

Computer codes for the solution of the Navier-Stokes and mass transfer equations have been

developed and mass transfer results have been obtained for Peclet numbers of 0(102). A Monte

Carlo code for larger Peclet numbers is being developed. The equipment for the experiments has

been constructed.

University of Colorado

Dept of Mechanical Engineering $128,866

Boulder, CO 80309-0427

Electromechanical Behavior and Properties of High-Tc Superconducting Tapes

S. Datta

The objective of this research program is to develop a fundamental understanding of the

electromechanical behavior of high-Tc superconducting tapes, and to rigorously establish the

connection between thermomechanical response and transport properties (critical fields and

currents). We are motivated by the recent progress that has been made in developing longlength, finite-width Bi-based tapes for industrial applications at both liquid nitrogen and liquid

helium temperatures, and the recognition that thermomechanical phenomena (stresses, cracking,

damage) during both processing and service have significant impact on the realizable critical

currents of these tapes. The research focuses on modeling the complicated three-dimensional

Engineering Research 15 1997

Engineering Research 15 1997
stress state in superconducting tapes when subjected to thermal and multiaxial mechanical

loading. Features of the materials that complicate analysis include the strong anisotropy of the

oxide superconductor, the inelastic constitutive behavior of the stabilizing metal, and the

temperature dependent material properties of both the superconductor and metal phases. Our

studies will provide a fundamental understanding of thermomechanical behavior and failure

mechanisms. They will quantify the influence of controllable parameters such as layer thickness

and interface toughness, and will identify strategies to tailor mechanical failure modes to optimize

electrical performance. We will correlate our analyses with critical current measurements to

determine the intrinsic and extrinsic effects of stress on superconducting properties. We will also

study, both theoretically and experimentally, the propagation of ultrasonic waves in the

superconducting tapes with the aim of providing valuable mechanical property characterization.

The ultrasonic study will specifically address the effect of the finite width of the tape on elastic

guided waves and will be closely coordinated with the laser ultrasonic study at Idaho National

Engineering and Environmental Laboratories by Dr. K. Telschow. While our study focuses on

primarily on high-Tc superconducting tapes, the theoretical and experimental framework is quite

broad, having numerous other applications including the analysis of multilayer actuators, multichip

modules in electronic packaging, coated and graded materials, and failure of bonded or welded

parts.

Cornell University

Mechanical & Aerospace Eng $89,469

Ithaca, NY 14853

Nonlinear Dynamics and Control of Large Arrays of Coupled Oscillators: Application to

Fluid-Elastic Problems

F. Moon

The goal of this study is to investigate the development of low dimensional models for fluid-elastic

phenomena. In the Comell research we have focused on the flow of air around a row of flexible

circular cylinders which is typical in heat-exchanger systems. In the past year we have obtained

both theoretical and experimental results. These results concern the nature of the bifurcation or

critical flow velocity at which the tubes loose stability and also on the nature of the unstable mode

of coupled-tube vibrations. In summary we have observed the following:

I) we have experimental evidence for a sub critical Hopf bifurcation;

ii) the critical speed for bifurcation decreases as the number of flexible cylinders increases;

iii) the unstable vibration mode has the nature of coupled helical wave solutions;

iv) a theoretical model has been developed, based in part on measured fluid-elastic

constants, which shows both the decrease in critical flow velocity with number of flexible

tubes and shows the helical wave solutions.

The current year's effort is directed toward pursuing the nature of the nonlinear terms in the

theoretical mode responsible for the sub critical Hopf bifurcation that has been observed in

experiments.

Engineering Research 16 1997 Research 16 1997
In a separate study, we have also explored controlling chaos in mechanical systems with impact

and friction. These experiments are modeled after the theoretical work of Ctt, Grebogi, and Yorke

at University of Maryland and the experiments of Hunt at Ohio University. We have designed and

implemented a circuit and actuator that can suppress chaos in an impact oscillator as well as one

with dry friction. This result may be relevant to control of fluid-elastic tube vibrations under

impact.

Cornell University

Sibley School of Mech & Aero Eng $141,131

Ithaca, NY 14853

Experiments on Velocity and Scalar Fields in High Reynolds Number Laboratory Flows

Z. Warhaft

Turbulence commonly occurs in chemical reactions, combustion, mixing, pollution and flow

around vehicles (causing high drag). In many of these problems progress is hindered because

of our ignorance of turbulence structure and dynamics. By means of fundamental experiments

we attempt to shed light on basic turbulence structure, in particular at the small scales where it

is thought that the turbulence behavior becomes universal, i.e., it is independent of the particular

way it has been generated.

In order to do these studies, highly energetic turbulence must be generated so that the small

scale structure can be achieved. We have recently developed active grids that can produce

turbulence at (Taylor-scale) Reynolds numbers close to 1000; much higher than that achievable

using the very largest computers (both now and for the foreseeable future). We have just

completed studies of scalar mixing, and the effects of Reynolds number variation in flows with

and without shear. In particular we have found incipient small scale anisotropy in both the scalar

and velocity fields. This suggests that turbulence models will have to be more subtle in dealing

with small scale structure and we will have to modify our ideas on the physics of the mixing

processes in high Reynolds number turbulent flows.

Dartmouth College

Thayer School of Engineering $127,684

Hanover, NH 03755

Two-Phase Potential Flow

G. Wallis

The objective is to develop results for well-defined situations that will serve as a basis for

evaluating or developing specific terms, particularly those involving fluid inertia, in basic models

of two-phase flow. During the last year emphasis has been on the "drift force" on a particle in an

inviscid flow with vorticity. Basic theory, experiments and CFD simulations complement each

other and substantially agree. Experiments, analysis and CFD simulations are also being used

to study transients in fluidized particulate systems, particularly those involving slugs, shock waves

and expansion waves.

Engineering Research 17 1997 Engineering Research 17 1997
Duke University

Dept of Physics $0

Durham, NC 27706

Experimental and Analytical Investigations of Flows in Porous Media

R. Behringer, G. Johnson, J. Georgiadis

Research Objectives: The objectives of this project include the characterization, both theoretical

and experimental of fluid flows through porous media. The particular focus is on fluid convective

flow in porous media. Convection in porous media occurs, for instance, when a layer of

fluid-saturated porous media is heated from below.

The characterization of porous convections includes both pure fluids and mixtures of different

fluids. Long term benefits will be an improvement in the theortical and practical applications of

flow in porous media in the presence of temperature gradients. Relevant practical situations

include petroleum and hydrology problems where heating occurs.

Scientific Approach: The primary approach is experimental, and involves the use of Magnetic

Resonance Imaging (MRI) as a powerful new tool to see the flow inside of porous media. The

project involves the use of a MRI apparatus and a precision thermal apparatus for carrying out

the convection experiments. Additional theoretical work now includes an analysis of-the

convective model equations with the goal of understanding recent experimental results. These

results show a strong coupling between the solid structure of porous media and the flow states.

Current Status of Project: Recent work has been described in Shattuck et al. Phys. Rev. 75,

1934 (1995). These experiments show the strong coupling between pore space structure and

flow patterns. An additional longer paper is in progress. This work forms the basis of Mark

Shattuck's thesis. Continuing work will focus on experimental MRI studies of binary mixture

convection in porous media.

Florida State University

Supercomputer Computations $106,090

Research Institute

Tallahassee, FL 32306

Theoretical and Computational Studies of Pattern Formation

J. Vitals

We seek to improve our understanding of the mechanisms underlying the formation of complex

spatio-temporal patterns in systems that are driven outside of thermodynamic equilibrium, to

characterize the macroscopic properties of such states, and to apply the methodology to

situations of interest in Materials Science, materials processing and Engineering. Two avenues

of research are being pursued: Patterns and chaos in fluids, and an order parameter formulation

of two-phase fluids. In the former, we utilize amplitude and order parameter equations to describe

the formation of pattems, their instabilities and the transition to chaotic states in extended

systems. In the latter, we introduce and order parameter formulation to describe moving boundary

problems in two phase fluids, and consider microstructure evolution in systems not readily

tractable with conventional hydrodynamics.

Engineering Research 18 1997
Georgia Institute of Technology

Computational Mechanics Center $88,993

Atlanta, GA 30332

Residual Life and Strength Prediction and Life-Enhancement, of Structural in Aging

Energy Production Systems

S. Atluri

The objective of this reseach project is to study the structural integrity and damage tolerance of

aging energy systems. In collaboration with the Fracture Mechanics Group at the University of

Washington, hybrid experimental-numerical analyses are being carried out, to establish an

energy-like parameter to characterize elastic-plastic and creep fracture that may occur in high

temperature pressure vessels. The T* integral parameter is being developed as a candidate

parameter. Using :(i) analytical solutions for linear elastic infinite domains containing line or planar

cracks, the faces of which are subjected to arbitrary tractions, (ii) the finite element method to

model the uncracked structure, and (iii) the generalized radial return algorithms for plasticity and

creep, a cost-efficient and accurate Inelastic Finite Element Alternating Method is being

developed. Elastic-plastic analyses of stable tearing in 2- and 3-D situations, using the IFEAM are

being carried out. Finally, strategies for life extension of energy systems, using composite repairs

are being studied.

Idaho National Engineering and Environmental Laboratory

Energy Res & Applications Dept $655,000

Idaho Falls, ID 83415

Fundamentals of Thermal Plasma Processes

J. Flncke

This project is of a coordinated experimental-theoretical research project on thermal plasma

processing of materials. This work is primarily focused on the development of advanced

diagnostic and computational techniques and their application to obtain a better and more

detailed understanding of the fundamental physical and chemical processes occurring in

nonequilibrium thermal plasmas with entrained particles. The techniques thus developed and the

information and insights they provide, can then be directly applied to process design, optimization,

and scale-up. The diagnostic and computational techniques already developed under this project

now represent the state of the art in this area. During the next five years of this project, we

propose to further extend and generalize these techniques to permit their application to several

additional topics of timely importance in the thermal plasma processing of materials, namely (1)

functionally gradient materials (FGMs), (2) reactive plasma spraying and (3) plasma chemical

synthesis of nanophase materials. These topics share some common features and physics which

make it efficient and cost-effective to consider them together. They form a natural progression

and will be pursued sequentially in the above order, but with significant overlap.

Enineering Research 19 1997 Engineering Research 19 1997
Idaho National Engineering and Environmental Laboratory

Materials Science Division $200,000

Idaho Falls, ID 83415

Application of Intelligent Control Systems to Mixed-Culture Bioprocesses

J. Johnson, D. Stoner

Even though the control of biologically-based processes is an extremely complex, multi-task

activty, conventional control systems operate at the most rudimentary of levels. That is, standard

set point control and alarm systems are used to monitor and maintain process parameters, while

process performance and recovery from upset conditions are dependent on the operator's

judgment and experience. Artificial intelligence has the potential of incorporating a human's

experience and rationale for the supervision of a bioprocess into a computer controlled system,

thus, radically changing the manner in which bioprocesses are supervised and controlled. The

challenges that confront the development of intelligent systems for bioprocessing control are due

to the limitations of the intelligent technologies; the manner in which these technologies may be

integrated into a control system; and the limitations inherent in the mathematical models that are

used to describe microbial metabolism and activity.

The overall goal of this program is to demonstrate that the productivity of bioprocesses can be

improved by integrating intelligent systems with conventional bioprocess control technologies. In

addition, the project will demonstrate the application of intelligent control to a complex system that

no analytic model can adequately describe. Investigators at the Idaho National Engineering

Laboratory have designed, built and evaluated hierarchical hardware and software systems for

the intelligent control of continuous flow, stirred tank reactors. The control system was developed

and evaluated using Thiobacillus ferrooxidans, a microorganism for which there is a moderate

amount information. This learning-based control system was successfully applied to an

uncharacterized culture of iron-oxidizing thermophilic microorganisms.

The hierarchical control systems had, as their lower level platform, an integrated system of set

point control, data acquisition, data analysis and equipment diagnostics programs. The control

system used on-line sensors and off-line measurements to determine the state of the system. A

two-level control system determined what actions were required to meet process goals. These

actions were carried out by computer controlled actuators, including pumps, gas-flow valves, a

heater, and a stirrer. The upper level of the control system, the supervisory control system, used

stochastic learning to determine what the system parameters, e.g., pH, dilution rate, and

temperature, should be, based on the state of the system. Lower level fuzzy systems and

standard classical methods implemented the controllers that operated the system. A diagnostic

system analyzed the sensor data for inconsistencies and provided a log of the system operation.

Engineering Research 20 1997
Idaho National Engineering and Environmental Laboratory

Materials Technology Group $369,000

Idaho Falls, ID 83415-2218

Elastic-Plastic Fracture Analysis Emphasis on Surface Flaws

W. Reuter, J. Epstein, W. Lloyd

The objective is to improve design and analytical techniques for predicting the integrity of flawed

structural components. Tests are being conducted on materials ranging from linear elastic to fully

plastic. The latter extends beyond the range of a J-controlled field. Specimens containing

surface cracks are used to simulate the fracture process (crack growth initiation, subcritical

growth, and catastrophic failure) that may occur in structural components.

Metallography and microtopography techniques have been developed to measure crack tip

opening displacement and crack tip opening angle for comparison with analytical models. Moire

interferometry techniques are used to evaluate and quantify the deformation in the crack region.

These studies have resulted in the ability to predict crack growth initiation of specimens

containing surface cracks using constraint and fracture toughness data obtained from standard

fracture toughness specimens. Results are being transferred to industry in the form of an ASTM

Test Standard on Surface Cracked Specimens (Structures) that is presently being developed.

Due to the complexity of studying the fracture process in weldments, diffusion bonded specimens

were used initially to simulate a weldment. This provided an opportunity to study the fracture

process in a model weldment of either a butt weld or a single "V" groove geometry that contained

neither a heat affected zone nor residual stresses. This work has been completed. Two

weldments have been fabricated using commercial ship building technology for a single "V"

groove with one having matched weld metal and the second an overmatched weld metal.

Another weldment has been fabricated using a one-half "K" weld joint design Characterization

of the microstructure and of local tensile properties is presently in progress. Testing of fracture

toughness specimens, specimens containing surface cracks, and modified specimen geometries

has been initiated.

Idaho National Engineering and Environmental Laboratory

Materials Technology Group $508,000

Idaho Falls, ID 83415

Intelligent Control of Thermal Processes

H. B. Smartt, J. A. Johnson

This project addresses intelligent control of thermal processes as applied to gas metal arc

welding. Intelligent control is defined as the combined application of process modeling, sensing,

artificial intelligence, and control theory to process control. The intent of intelligent control is to

produce a good product without relying on post-process inspection and statistical quality control

procedures, by integrating knowledge of process engineering practice and process physics with

real time weld quality and process state sensing into control algorithms. The gas metal arc

welding process is used as a model system; considerable fundamental information on the

process has been developed at INEL and MIT. Research is being conducted on analytical

modeling to couple nonlinear aspects of molten metal droplet formation and transfer with base

Engineering Research 21 1997
metal melting and resultant weld pool geometry, and integration of knowledge-based control

methods (including artificial neural networks and fuzzy logic based connectionist systems) with

iterative learning control methods. Results are being transferred to industrial partners through

a related DOE-EE CRADA on Intelligent Diagnostics, Sensing, and Control of Thin Section

Welding, and a work-for-others CRADA to an industrial end user.

The focus of present work is specifically on develoment of real time optimal parameter selection

for pulsed current gas metal arc welding of steel and aluminum structures. This work is being

conducted in collaboration with a related DOE-BES welding fracture mechanics program being

conducted at INEEL and MIT and is expected to be of significance for the petrochemical,

shipbuilding and automotive industries.

This project is part of a collaborative research program with the Massachusetts Institute of

Technology.

Idaho National Engineering and Environmental Laboratory

Nondestructive Mat'ls Charac Grp $180,000

Idaho Falls, ID 83415-2209

Coupled Mode NDE

K. L. Telschow

Many engineering material applications lack microstructure characterization methods that are both

applicable to the industrial environment and provide sufficient selectivity for features of interest,

such as fatigue, residual stress, or specific microstructures. However, small changes in

magnetization often accompany microstructural changes in industrial materials brought about by

effects related to aging, lifetime reduction, and the manufacturing process that could be used as

selective probes. High Temperature Superconducting Quantum Interference Devices

(HTS-SQUID) technology offers the prospect for measuring these small magnetizations due to

high sensitivity and wide dynamic range. This research program is seeking new selectivity in

nondestructive evaluation (NDE) through local measurement of small magnetizations that arise

from the dynamics of material properties brought about by electromagnetic, elastic, or optical

perturbations ("coupled modes"). Selectivity comes from the material?s nonlinear interaction

terms in the internal energy that can be differentiated by this coupled mode approach. Combined

magnetic and ultrasonic assessments of materials in tape form and local measurement of fatigue

damage in stainless steel piping are being pursued. The work builds on previous NDE research

conducted at the INEEL based on noncontacting electromagnetic measurement of the

superconducting properties of tapes, measurement of fatigue and aging in stainless steels, and

optical ultrasonic measurement methods.

Engineering Research 22 22 1997
U U

University Of Illinois

Coordinated Science Laboratory $144,864

Urbana, IL 61801

Optimization-Based Robust Identification and Control of Uncertain Dynamical Systems

T. Basar

This program involves fundamental research on optimization-based robust identification and

control of uncertain dynamical systems. The class of systems considered includes large scale,

stochastic, nonlinear, hybrid, and distributed parameter systems, all subject to different types of

static as well as dynamic uncertainties. The optimality criteria adopted include minimax,

risk-sensitive, and receding horizon formulations. The main theme is optimality-based

identification, control, and model simplification under severe internal and external uncertainties.

Research involves not independent, but a combined design of observer/filter and control

architectures, supported by optimization-based model-reduction, decomposition and aggregation

techniques.

One area of current research is the derivation of optimally disturbance attenuating controllers for

nonlinear systems in a receding horizon framework, when full state measurements are not

available. This way an implementable controller structure can be obtained, instead of the

infinite-dimensional one the original problem admits. Another topic of current study involves

robust control of nonlinear systems whose dynamics are unknown, where some neural network

architectures are incorporated into the design. Yet another topic is the derivation of robust

controllers for some classes of uncertain infinite dimensional systems, and systems which

undergo structural changes governed by a stochastic process.

University Of Illinois

Dept of Chemical Engineering $155,000

Urbana, IL 61801

Gas-Liquid Flow in Pipelines

T. Hanratty

Many operations in the petroleum industry involve the flow of gas and liquid in pipelines.

Examples are offshore oil platforms and the transportation of natural gas in pipelines. The

economic and safe design of these systems is handicapped because of difficulties in predicting

how the phases distribute. Considerable progress has been made by relating large scale

behavior to small scale interactions between the phases.

Slug flow is a pattern that exists in horizontal flows whereby slugs of highly aerated liquid flow

intermittently along a pipeline. Of critical importance is the prediction when this pattern will exist

and the prediction of the frequency of slugging. Usual practice is to examine the stability of a

stratified flow, where the liquid flows along the bottom of a horizontal pipe and the gas

concurrently above it. A different approach, which involves a study of the stability of slugs,

provides an explanation of the initiation of slugging at high gas velocities and at high pressures.

Measurements of the time and spatial variation of the liquid height along a pipeline is providing

the physical understanding of the formation of slugs needed to predict frequency.

Engineering Research 23 997 Engineering Research 23 1997
U U

An important configuration which appears in condensers and evaporators, as well as in petroleum

pipelines, is annular flow. Part of the liquid flows along the wall and part as drops entrained in

the gas. A critical problem in horizontal pipes is the prediction of asymmetries due to gravity.

Experimental results on these asymmetries are being used to improve our ability to improve

present design methods. This work will be particularly important to understanding the

performance of large diameter pipes for which the transition from stratified to annular flow occurs

over a wide range of gas velocities.

University Of Illinois

Aeronautical and Astronautical $72,282

Engineering

Champaign, IL 61801

Nonlinear Dynamics of Parametrically Excited Gyroscopic Systems

S. Namachchivaya

Gyroscopic systems are an important class of systems which include such problems as rotating

shafts, supported pipes conveying fluid, systems subject to Lorenz forces, structures moving in

fluid media, transverse vibrations of moving belts, etc. In these gyroscopic systems, there are

many situations in which the system is parametrically or stochastically excited. For example, the

rotating shaft may be subject to periodic or random perturbations in its applied end load or

rotation rate, due to its interaction with other components. The pipe conveying fluid may be

subject to similar structural excitations, as well as periodic or random fluctuations in the fluid flow

rate. Such disturbances can lead to modal interactions, large amplitude oscillations, chaotic

behavior, etc.

The primary goal of the research is to study the local and global dynamics of gyroscopic systems

subject to periodic and random excitations, and to numerically and experimentally verify the

theoretical results. The results of this research will be useful in such applications as rotating

shafts, pipes conveying fluid, etc. The objectives of the research are as follows:

* In the first part of the research, the nonlinear equations of motion governing a general

gyroscopic system will be systematically derived. The equations will include the effects of

parametric/random excitation, symmetry-breaking, and linear and nonlinear dissipation. In

addition, equations will be derived for several physical examples which are gyroscopic systems.

* In the second part of the research, the local bifurcations associated with the discretized

equations of motion will be examined. Furthermore, physical applications contain inherent

imperfections which break the symmetry of the problem. Such symmetry-breaking imperfections

may give rise to local and global bifurcations. The effects of symmetry and the associated

reduction of nonlinear equations, along with symmetry-breaking bifurcations, will also be

examined. The results will then be interpreted for each of the physical applications.

* In the third part of the research, the mechanisms which give rise to global bifurcations in

gyroscopic systems will be fully examined. The focus of this part is the development of general

analytical techniques to predict global behavior in this class of systems. We propose to develop

Engineering Research 24 1997
a method of predicting these global phenomena in a systematic manner. In addition, the local

and global behavior predicted using analytical methods will be compared with the behavior

observed numerically using continuation methods, numerical integration of discretized equations

of motion, etc. Once again, these results will be interpreted in light of the specific physical

applications.

* In the fourth part of this research, mathematical techniques will be developed to determine

the stationary solutions and their almost-sure stability properties for nonlinear gyroscopic systems

which are stochastically excited. In addition, mechanisms which give rise to stochastic

bifurcations in nonlinear random dynamical systems will be studied.

* In the final part of this research, dynamic experiments will be conducted on a rotating shaft

to verify the theoretical results obtained. These dynamics experiments will locate the stability

boundaries and examine the nature of the nonlinear response. The numerical and experimental

results will, in turn, guide the development and refinement of the theories to incorporate any new

phenomena observed.

University Of Illinois

Dept of Mechanical and $82,179

Industrial Engineering

Urbana, IL 61801

Origins of Asymmetric Stress-Strain Response in Phase Transformations

H. Sehitoglu

A number of uniaxial and stress state experiments on the NiTi alloys that are known to undergo

thermo-elastic phase transformations were conducted. Unlike steels which exhibit virtually no

recoverable transformation strains, the transformation strains in this class of materials are

partially recovered upon unloading, depending on the applied strain levels. Using a servohydraulic

intensifier, a servohydraulic test machine, and a novel pressurized test chamber; pressures of

750MPa and axial stresses of almost any magnitude are simultaneously generated and applied

to the gage section of a solid, cylindrical NiTi specimens. The work utilizes a robust internal load

cell that can measure axial forces without the effect of seal friction and demonstrate innovative

ways of calibrating this load cell, and methods of axial and circumferential strain measurement

in a pressure environment and verify accuracy of these results. Constitutive models proposed in

the literature for thermo-elastic transformation were evaluated in light of these results. The current

models predict that the volume fraction of martensite is solely dependent on the effective stress.

Our experimental results indicate that there is a dependence of the transformations strain on the

hydrostatic stress component with strong asymmetry in tension versus compression. In view of

these experimental findings, new transformation models are being developed incorporating the

low symmetry of the twinning planes. The stress-induced phase transformation of CuZnAI was

also found to be stress state dependent but less so than NiTi.

Engineering Research 25 1997
U U

Johns Hopkins University

Mechanical Engineering Dept $120,163

Baltimore, MD 21218

Two-Fluid Averaged Equations for Multi-Phase Flow

A. Prosperetti

The ultimate purpose of this study is to develop accurate averaged-equations models of disperse

multi-phase flows of engineering significance. For this purpose, a method has been devised by

which direct numerical simulations are used systematically to derive -- rather than "guess" -- the

terms that are left undetermined by the averaging procedure.

In this work a particular emphasis is placed on the calculation of terms involving spatial

derivatives of the averaged quantities, that are essential for the stability and hyperbolicity of the

model. In the past no technique capable of giving insight into these terms has been available,

other than at very low volume fractions.

The main difficulty that had to be overcome in the development of this approach has been the

ability to calculate such terms -- which inherently refer to non-uniform suspensions -- relying on

techniques developed for uniform suspensions. This was an unavoidable step as it is only in the

uniform case that sufficiently powerful computational algorithms are available. A new approach

capable of achieving this end has been developed and has been successfully implemented for

the case of heat conduction in a composite. Work on Stokes flow is near completion, and the

opposite limit of high-Reynolds-number flow has also been addressed with promising results.

Robert H. Kraichnan, Inc.

369 Montezuma 108 $77,370

Santa Fe, NM 87501-2626

Turbulence Theory and Reduced Hydrodynamics

R. Kraichnan

Turbulent flow is omnipresent in geophysics and energy-producing devices. Atmospheric turbulent

transport plays an essential role in the movement of heat, moisture, and pollutants. Turbulent

flows represent an enormous amount of data. Both for practicable computation and for physical

understanding, it is necessary to extract the essential information in compact form. This project

explores novel approaches to economical description and computation of turbulence. Explicit

statistics have been deduced theoretically for the spottiness of small scales of a contaminant

carried by turbulence. This is the first such success for a turbulence problem, and has sparked

an intense and continuing international follow-up effort. The theoretical work has been used

under this Grant to guide computer simulations of unprecedented resolution. Recent attention

has been focussed on intermittent velocity fields. A result of this project should be improved,

economical computation of contaminant dispersal and mixing. Current work has extended the

theoretical understanding of intermittency) to the prediction of new features (including a new

scaling range) in one-dimensional model flow equations.

Engineering Research 26 1997

Engineering Research 26 1997
Lawrence Berkeley National Laboratory

Dept of Physics $135,000

University of California

Berkeley, CA 94720

Studies in Nonlinear Dynamics

A. Kaufman, R. Littlejohn

This research is devoted to the development of new methods for analyzing the evolution of waves

and other dynamical systems. The primary approaches are Hamiltonian and Lagrangian, utilizing

phase-space-geometric methods and variational principles. The wave-fields studied are typically

multi-component, so that polarization and geometric-gauge concepts are important. Particular

emphasis is placed on mode-conversion processes. Current projects include: (1) The resonant

interaction and energy transfer between an eastward propagating equatorial-wave-guide

Rossby-gravity wave and a westward propagating coastal Kelvin wave; (2) Auto-resonant

phase-locking of such guided waves by nonlinear freqency shifts; (3) Tangential mode

conversion, in which ray curvature dominates the interaction process; (4) Correlated emission

of waves in a mode-conversion region; (5) Effect of polarization-dependent dissipation on the

double-conversion process.

Another project involves the exploration of the theoretical underpinnings of non-imaging optics,

a new field of optics in which the emphasis is typically on the detection, transport and/or

concentration of radiant energy, rather than the formation of an image. Nonimaging optics is

important in solar energy technology, infrared countermeasures, and other areas. Our work in

recent years has concentrated on an elucidation of the fundamental principles of nonimaging

optics, starting from electromagnetic theory. This is another area in which phase space

representations of wave fields and other phase space techniques have been important. For

example, in a recent paper we have shown how one may measure the phase space distribution

of an optical field.

Lawrence Livermore National Laboratory

Laser Programs, L-482 $100,000

University of California

Livermore, CA 94551

Steady State and Transient Nucleation Kinetics

G. Wilemski

This research addresses several fundamental issues in homogeneous nucleation theory.

Currently, the appealing simplicity and wide applicability of classical nucleation theory is offset by

its inaccurate predictions of nucleation rates. On the other hand, new molecular theories of

nucleation appear capable of providing greatly improved predictions, but practical application of

these theories is currently restricted to the simple rare gas systems. The status of binary

nucleation theory is further clouded by the inability to test theoretical predictions about the

compositional structure of mixed nanodroplets because of the lack of direct experimental data on

this phenomenon. The goals of this research are threefold: (1) to provide the theoretical

underpinning for a powerful new analysis technique, small angle neutron scattering (SANS) from

g r

Engineering Research 27 1997
nanodroplet aerosols, that can probe the compositional structure of nanodroplets, (2) to explore

ways of bridging the gap between fundamental molecular nucleation theories and

phenomenological approaches based on thermodynamic reasoning, and (3) to test and improve

binary nucleation theory.

The importance of small angle neutron scattering from aerosols (aerosol SANS) stems from its

potential to probe directly the microscopic structure of the nanometer-sized droplets. Particles

in this size range are the first condensed phase fragments to appear during aerosol formation.

Aerosol SANS measurements also yield considerable detail about the particle size distribution of

the aerosol allowing stringent testing of theories of nucleation and droplet growth under conditions

of high supersaturation. The aerosol SANS technique relies on a supersonic nozzle expansion

to reliably produce a steady flow of aerosol. The measured scattering patterns are anisotropic

because the high directed velocity of the particles Doppler-shifts the momentum of the scattered

neutrons. The basic theory needed to properly analyze these scattering patterns has been

developed, and refinements are being pursued. Modeling of both unary and binary nucleation and

droplet growth is also underway to both predict and interpret the experimental scattering patterns.

Nucleation rates in nozzles are extremely high, and the corresponding critical clusters contain ten

to twenty molecules. To improve the theory of nucleation under these extreme conditions an

effort is being made to develop theoretical expressions for cluster evaporation rates based on

computer studies of small clusters of more complex molecules such as water and methanol.

Theoretical work is also being done to test and improve various aspects of binary nucleation

theory. The birth-death equations are accurately solved numerically to simulate binary nucleation

kinetics for fluid systems with strong compositional surface enrichment, partial miscibility, and

significant vapor phase nonideality. These results are then used to assess the accuracy and

applicability of various approximate analytical expressions for the rate of binary nucleation. The

results of these investigations also provide valuable input for the aerosol SANS modeling work.

The Lovelace Institutes

Institute for Basic and Applied $52,350

Medical Research

Albuquerque, NM 87108

Two-Phase Flow Measurements by Nuclear Magnetic Resonance (NMR)

E. Fukushima, S. Altobelli, A. Caprihan

The objective is to apply nuclear magnetic resonance (NMR) to study how mixtures of different

phases diffuse and flow. NMR has been used to non-invasively measure concentration and

velocity of suspensions undergoing steady flows at Lovelace. A future aim is to measure flow

parameters for both phases of a solid-liquid mixture by utilizing the relaxation rate difference

between the two components. Because the usual NMR measurements, especially imaging, are

slow, an obvious goal is to develop methods to take data much faster. One approach to this

objective is to develop a hardware compensation circuit to reduce the distortion of the magnetic

field gradient pulses caused by eddy currents induced in conducting surfaces in and around the

NMR sample. The other is to develop dedicated hardware that performs rapid computations

resulting in real-time image reconstruction from the data. Vibrating beds of granular material are

difficult to study by conventional optical methods because of their opacity. They are not easy by

NMR, either, because the flow is not in steady state, i.e., the sample configuration changes with

Engineering Research 28 1997
time even though the variation is periodic. The periodic nature has been used to gate the imaging

sequence to the motion resulting in 3-D images of shaking granular beds. In this way, sharp

spikes of particles on the surface of the bed have been imaged for the first time. An ultimate

target of this project is to be able to measure a periodic nonsteady flow such as bubbly flows and

turbulence.

McDermott Technology, Inc.

Research and Development Division $151,631

Alliance, OH 44601

Investigation of Law Temperature Time Dependant Cracking

W. A. Van Der Sluys

This project is investigating the metallurgical and mechanical phenomena associated with the

occurrence of time dependent cracking of carbon steels at temperatures between 620°F and

680°F. Time dependent cracking failures of carbon steel piping in this temperature range have

been experienced in the fossil power industry for the past twenty years. Moreover, the

catastrophic failures occurred suddenly, creating a serious threat to human safety and substantial

monetary losses. Research programs conducted to address this problem have demonstrated that

this type of failure is proceeded by time dependent crack growth. Recent field failures

demonstrate that our understanding of the fundamental metallurgical and mechanical parameters

controlling this type of failure, are insufficient to eliminate it from the field.

This project is therefore focused on the metallurgical phenomena associated with low

temperature time dependent crack growth in carbon steels. The project has been separated into

two phases, the physical metallurgy phase associated with time dependent changes occurring

in the crack tip region, and critical mechanical metallurgy experiments to quantify the time

dependent cracking susceptibility of carbon steels.

Time dependent cracking is strongly linked to the content of residual elements in the steel

composition. To address the composition issue, four heats of steel with varying combinations of

residual element contents have been obtained. The compositions of these heats are such that

correlations between cracking susceptibility and bulk residual element are being studied.

University Of Maryland

Dept of Mechanical Engineering $0

College Park, MD 20742

Characterization of Metal Cutting Dynamics

B. Berger, I. Minis

The development of energy efficient machine tools which produce parts of high quality and

require minimum intervention requires the capacity to identify precursors of unstable, chatter

states and integrate such identifiers into control system algorithms. Large amplitude oscillations

associated with chatter adversely effect surface finish, dimensional accuracy and tool wear often

resulting in tool breakage.

Engineering Research 29 1997
This research effort has addressed the fundamental issues involved in the identification and

control of chatter through: (i) creation of a data base of over 200 cutting experiments comprising

16-107 separate measurements for ranges of values of depth of cut, turning speed and feed rate;

(ii) analysis of time series in the data base with a variety of techniques including false nearest

neighbors, mutual information, singular value decomposition, wavelet and polyspectral methods;

(iii) identification in the data analysis of three non-dimensional measures of the cutting state which

are sufficiently robust for use in the on line control of the cutting machine; (iv) incorporation of the

measures of the cutting state into the control system of a Harding Superslant AB CNC lathe.

The three measures of the cutting state, (iii), are based on the ratio of singular values of an

unsymmetric Toeplitz matrix of third order cumulants, a wavelet decomposition of cutting force

data and a cutting force averaging process, respectively.

University Of Maryland

Dept of Electrical Engineering $104,000

College Park, MD 20742

Mathematical Models of Hysteresis

I Mayergoyz

This research is concerned with nonlinear diffusion of electromagnetic fields in hysteretic media.

Examples of such media are ferromagnetic conducting media with magnetic hysteresis and

superconducting media with sharp or gradual resistive transitions.

The main research objectives of the project can be briefly summarized as follows: development

of analytical techniques for the calculation of eddy currents in magnetic media with hysteresis for

linear polarizations of magnetic field (scalar problems), analysis of eddy currents in isotropic and

anisotropic media with hysteresis for vector polarizations of magnetic field (vector problems),

further development of mathematical models for hysteresis in superconductors with gradual and

sharp resistive transitions, development of nonlinear impedance type boundary conditions for

hysteretic media and their finite element implementation. It.is hoped that, as a result of this

research, new analysis techniques will be developed which will find numerous applications in

such areas as nondestructive testing, magnetic recording, design of superconducting magnets,

induction heating, electromagnetic shielding, evaluation of power losses, etc.

University Of Maryland

Electrical Engineering Department $136,749

Baltimore, MD 21228

Pulse Propagation in Inhomogeneous Optical Waveguides

C. Menyuk

Our current investigations are focused on two overlapping subjects. The first is

dispersion-managed solitons. It has recently been discovered that the same sort of dispersion

map that has trditionally been used for non-return to zero signal transmission can be productively

En erig R arch 30

Engineering Research 30 1997
U U

used for what we refer to as disperiosn-managed solitons. These are signal pulses that

periodically return to their initial shape after every pas though the dispersion map, although they

undergo a large amount of distoriton during each pass. We are investigating these signals both

theoretically and experimentally; to date, we hold the world's record for distance x time products

in an unguided system, and we have developed new procedures for calcualting the noise

contribution that we believe could significantly impact these calculations for all communication

formats. The second subject concerns randomly varying birefringence in the optical fiber as it

interacts with polarization-dependent loss, polarization-dependent gain, and polarization mode

dispersion. Since the split step method cannot be used to effectively address these issues in an

environment with wavelength division multiplexing, we have established a new approach that

follows the Stokes parameters of each channel without addressing the intersymbol interference

in each channel.

University Of Maryland

Dept of Mechanical Engineering $0

College Park, MD 20742

Contaminant Dispersal in Bounded Turbulent Shear Flows

J. Wallace, P. Bernard, L. Ong

The purpose of this project is to better understand the physics of scalar transport and to develop

a methodology for the accurate prediction of scalar fields in highly sheared environments,

including the development of a new clasds of models that more accurately mimic the dynamical

processes affecting plume development. Of particular interest is the wall-normal diffusion of

scalars and its connection to vortical structures in the wall region, and the efficacy of the transport

models in both canonical boundary layer flows as well as in complex flow geometries with

significant flow separation. Towards these objectives, closely coordinated direct numerical

simulations (DNS) and windtunnel experiments of evolving line- source plumes have been

conducted.

Simultaneous flow visualization (using a laser light- sheet tomographic system) and velocity

measurements (using a 4-sensor hot-wire probe) were performed in a turbulent boundary layer.

A smoke plume seeped into the flow from a wall slot in the windtunnel idealized the dispersion

of a passive scalar pollutant released from a line source in the atmospheric surface layer. These

experiments have yielded detailed concentration contour maps as well as profiles of the

concentration fluxes that have been used for model development and verification.

Quasi-three-dimensional flow visualizations have been conducted with light sheets oriented in the

spanwise direction. Reconstruction of three-dimensional surfaces of constant concentration has

been accomplished. Finally, measurements of the concentration and concentration flux fields in

a boundary layer with a two-dimension square obstacle on the wall have been carried out. This

flow is an idealization of an urban canopy with a line scalar source at the wall.

Engineering Research 31 1997
Massachusetts Institute Of Technology

Department of Chemical Engineering $271,971

Cambridge, MA 02139

Synthesis and Optimization of Integrated Chemical Processes

P. Barton, L. Evans

The goal of this research program is to develop novel systematic methods for the design and

operation of chemical processes. As the chemical industry is one of the largest consumers of

energy in the US, it is important to find efficient and creative computer-aided strategies for

improving the efficiency of chemical manufacturing systems. One research thrust is addressing

the need for process design and optimization technologies for batch/semi-continuous processes,

which are increasingly important as the US shifts to the production of small quantities of high

value added products. Research is focusing on design tools for the rapid development of efficient

processes. The approach employed is based on the derivation of targeting models, which are

simplified models that can rapidly generate a number of promising design alternatives for more

detailed study. Since the targeting models also yield a rigorous lower bound on the cost of any

potential design, this information can be used to justify and guide subsequent optimization of the

design. In addition, the targeting models can be coupled with more detailed dynamic models to

derive the first rigorous approach to address simultaneously the discrete and dynamic decisions

in the optimization of a batch process design.

Secondly, complementary research is pioneering technologies for the optimization of large-scale

dynamic systems, particularly focusing on discontinuous problems (e.g., hybrid

discrete/continuous systems, inequality path constraints). Applications of interest include the

design of optimal plant-wide operating policies for batch processes, or optimal operating

procedures for start-up, shut-down and changeovers in continuous processes. A theoretical thrust

focusing on discontinuous problem formulation, structure and classification, is accompanied by

a numerical thrust that transforms the theoretical results into robust and efficient algorithms for

large-scale problems.

Massachusetts Institute Of Technology

The Energy Laboratory $364,736

Cambridge, MA 02139

Metal Transfer in Gas Metal Arc Welding in the High Current Regime

T. Eagar

Two coordinated modeling efforts were started in 1997. The overall goal of the work is to explain

droplet detachment and weld pool behavior in higher current modes typical in high productivity

industrial applications.

The first effort is to develop a dynamic model for simulating electrode melting, drop formation,

and drop detachment. Existing experimental results covering a wide range of welding parameters

in different transfer modes were reviewed. Heat input, contact tube to workpiece distance, and

shielding gas composition are parameters that will be included in ongoing modeling work.

Emphasis will be given to the physical effects which cause the transition from globular to spray

Engineering Research 32 1997
transfer. The model should predict size, frequency and heat content of the transferred drops over

a wide range of parameters.

The second model will predict the effect of molten metal flow, surface effects, and droplet

impingement on the weld pool. The model will contribute to control of weld defect formation such

as humping, tunnel porosity and undercutting. A simplified fully-coupled model for the weld pool

was developed, and it suggests that the weld pool tends to behave as a thin liquid film at high

currents. This could explain the "finger penetration" phenomenon.

Massachusetts Institute Of Technology

Francis Bitter Magnet Laboratory $93,324

Cambridge, MA 02139

Cryotribology (Low-Temperature Friction and Wear): Development of Cryotribological

Theories and Application to Cryogenic. Devices

Y. Iwasa, E. Rabinowicz

The main objective of this project is to develop a better understanding of mass transfer between

bubbles and impure liquids. New techniques will be developed that can be used to analyze mass

transfer in a broad range of problems. The focus is on bubbles between 0.5mm and 2.0mm in

water. Issues of particular interest are the transient period during which surfactants adsorb onto

the bubble and the effect of the transient on bubble dissolution.

The scientific approach involves laboratory experiments and numerical simulations. Experiments

will be done to measure the velocity and dissolution of bubbles in both pure water and water

containing controlled amounts of surfactants. The numerical simulations will provide information

about the flow and concentration fields around the bubble and the dependence of the transient

period on surfactant sorption kinetics. A new numerical technique will be used to simulate mass

transfer between a bubble and the surrounding liquid.

Computer codes for the solution of the Navier-Stokes and mass transfer equations have been

developed and mass transfer results have been obtained for Peclet numbers of 0(102). A Monte

Carlo code for larger Peclet numbers is being developed. The equipment for the experiments has

been constructed.

Massachusetts Institute Of Technology

The Energy Laboratory $198,451

Cambridge, MA 02139

Modeling and Analysis of Surface Cracks

D. Parks, F. McClintock

We are developing a mechanics basis for analyzing the fracture behavior of cracks located on

or near the fusion zones of structural weldments. Such welds are often characterized by

Engineering Research 33 1997

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significant strength mismatch between base plate and weld metal, as well as by local strength

gradients associated with metallurgical details of the heat-affected zones. Moreover, the local

gradients in microstructure, and the accompanying gradients in material resistance to both ductile

hole growth and cleavage fracture mechanisms provide additional complexity, compared to the

·corresponding fracture mechanics models of macroscopically homogeneous crack-tip

microstructures and properties.

Under macroscopic mode I loading, strength-mismatched interface crack-tip stress and

deformation fields show considerable differences from the corresponding fields in mechanically

homogeneous media. In particular, both triaxial stress and plastic strain levels in the softer

domain (e.g., an undermatched baseplate) are elevated. Families of mismatched fields have

been characterized by finite element and slip-line solutions, and have been shown to apply from

small-scale yielding through fully-plastic conditions.

The mismatched fields are being coupled with local models of cleavage and ductile fracture in

the inhomogeneous crack-tip region, and the results compared with experiments on both model

weldments created by diffusion-bonding and with actual welds in A710 steel.

Massachusetts Institute Of Technology

Dept of Chemical Engineering $383,422

Cambridge, MA 02139

Development of Principles & Methodologies of Metabolic Engineering

G. Stephanopoulos

Metabolic Engineering is an emerging field of biotechnology aiming at the directed modification

of the metabolic pathways of microorganisms, plants and animals using recombinant DNA

technology. The overall objective is to achieve overproduction of fuels, chemicals and materials,

or biosynthesis of novel products through the amplification of selected biochemical reactions or

the introduction of new biosynthetic pathways in metabolic networks. The experimental

techniques of metabolic engineering are derived from applied molecular biology and are well

advanced. However, interactions of metabolic pathways and the general principles governing

metabolic fluxes in-vivo are poorly understood. The goal of this research is to contribute to the

development of the tools and principles that elucidate the control of flux in metabolic networks.

As the problem of determining flux control distributions at the individual reaction level is too

complex and experimentally intractable, our approach has examined the control of flux exercised

by groups of reactions. Concepts from metabolic control analysis have been extended to groups

of reactions in order to identify the group exercising the strongest degree of control on the

production flux. The approach is then repeated within the group until single reactions are

identified that are of particular importance to the flux of product formation. This approach has

been applied with success to the production of aromatic and aspartate aminoacids in

Corynebacterium and yeasts.

A K

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Massachusetts Institute Of Technology1

Dept of Chemical Engineering $87,534

Cambridge, MA 02139

Los Alamos National Lab2

MEE-9 $80,000

Los Alamos, NM 87545

Sandia National Laboratories3

Engineering Sciences Center $100,000

Albuquerque, NM 87008-0834

Macrostatistical Hydrodynamics

H. Brennerj, A. Graham 2, L. Mondy3

Experimental, analytical, and numerical studies of falling-ball 'tracer' particle dynamics in

concentrated suspensions composed of dispersed, neutrally-buoyant spheres and rods

comparable in size to the tracer have been continued and extended. Falling ball viscometry

was shown to be a useful technique to measure the apparent viscosity of suspensions of

particles without unduly disturbing the initial configuration of the suspended particles. The

pressure 'drop' across a ball falling through a quiescent suspension, which constitutes another

useful dynamical suspension parameter, was measured and, in moderately concentrated

suspensions, found to agree well with theoretical results for the comparable pressure drop in a

homogeneous Newtonian liquid. For a ball falling in a highly concentrated suspension, the

pressure drop seems to be a sensitive measure of phase slip at the containing cylinder walls.

Also, spinning-ball rheometry in quiescent suspensions has been developed as a useful adjunct

to the falling-ball rheometric studies. This technique provides a sensitive measure of phase slip

at the spinning ball's surface, as well as another experimental benchmark for ongoing theoretical

investigations of slip in disperse systems. Finally, in collaboration with The Lovelace Institutes,

nuclear magnetic resonance imaging is being used to study flow-induced particle segregation

("hydrodynamic diffusion") in pipe flow. These data in inhomogeneous flows and complementary

video imaging of individual tracer particles in homogeneous flows will provide much needed

information on the effects of flow on particle interactions and effective rheological properties at

the macroscale. For example, the dispersion in velocity of tracer particles in an otherwise

transparent concentrated suspension undergoing homogeneous shear flow is currently being

measured using techniques developed in earlier falling ball studies. The resulting information on

the self-diffusion of a suspended sphere among like spheres is central to kinetic-theory-type

models of suspension flow.

Engineering Research 1997 35
University Of Minnesota

Dept of Mechanical Engineering $137,999

Minneapolis, MN 55455

Heat/Mass Transfer Enhancement in Separated and Vortex Flows

R. Goldstein

The flow and heat/mass transfer around single short-step and uniform diameter circular cylinders

are being studied. Flow visualization indicates that a short step diameter circular cylinder has a

much more complex vortex system than a uniform diameter circular cylinder due to vortices

formed on the steps of the cylinders. Velocity and turbulence measurements reveal that the

interaction between the vortices formed on the steps of the cylinder and those formed near the

endwall junction. change the vortex shedding frequencies (Strouhal Number) in the wake flow.

The measured local heat/mass transfer compares well with flow visualization and velocity

measurements, and confirms the vortex flow patterns.

Energy (total temperature) separation associated with unsteady pressure fluctuations, induced

by the convective movement of vortices has proved to have strong effects on heat transfer.

Energy and total pressure separation in and around a free circular jet, including the effects of

acoustic excitation, and the energy (total temperature) separation around a circular cylinder in

high speed flow are being investigated. For the flow in the vortex ring structure around a jet,

energy separation and the total pressure separation amplitude are greatly increased by acoustic

excitation. This excitation is expected to have a strong effect on the jet impingement heat/mass

which will be investigated. For the circular cylinders, the preliminary results show that the

dominant transient recovery temperature frequency on the cylinder surface in the wake region

matches the vortex shedding frequency.

University Of Minnesota

Dept of Mechanical Engineering $213,746

Minneapolis, MN 55455

Thermal Plasma Chemical Vapor Deposition of Advanced Materials

J. Heberlein

The objective of this project is to broaden the technical base for processing of diamond, yttria

stabilized zirconia and nanophase composite materials.

The studies related to diamond deposition have concentrated on characterizing the liquid injection

diamond deposition reactor using a combination of modeling and analysis of deposition results.

The model has been completed as a fully three-dimensional fluid dynamics and chemical kinetics

description of the reactor, including the atomization of the liquid precursor and the trajectories and

evaporation of the droplets. Various operating conditions have been simulated, and it has been

found that liquid precursors result in higher deposition rates if the liquid droplets reach the

substrate boundary layer before evaporating.

Engineering Research 36 1997
Investigations on yttria stabilized zirconia (YSZ) layers have concentrated on developing a

deposition technique using our unique triple torch reactor for generating very dense films which

can be used as electrolyte in solid oxide fuel cells. A fundamental limitation of plasma CVD has

been found, and a new process, center injection low pressure plasma spraying, has been

developed. Films have been deposited with this process at high rates (>60 m/min) with porosities

<0.5 %.

The spatially and temporally resolved characterization of turbulent non-equilibrium plasma jets

using laser scattering techniques developed at the Idaho National Engineering Laboratory has

confirmed the discrepancies found at INEL. Research efforts are now concentrating on comparing

assumptions required for the theoretical line shape derivation with the conditions present in the

experiment.

University Of Minnesota

Dept of Aero Eng & Mechanics $120,000

Minneapolis, MN 55455

Lubricated Transport of Viscous Materials

D. Joseph

The project has as its broad aim the understanding and technological development of lubricated

pipelines of heavy oils in core annular flow, and the spontaneous lubrication of oil/water and

water/oil emulsions and for slurry transport. The scientific approach relies heavily on experiments

and direct numerical simulations. Analytically the problem involves the study of two-phase flows

and deals with migration and segregation of lubricating fluid at the wall. The role of inertia in

centering density matched core-annular flows and in levitating these flows off the wall when the

fluids have different densities has been clarified in recent works sponsored under this grant.

Experiments on the effects of different linings and surfactants on the fouling of pipe walls with

hydrocarbons were carried out. A patent for a "method of preventing fouling of pipe walls for

lubricated transport" was obtained for cement linings (U.S. Patent No. 5,385,175). Another

patent for a non-fouling pressure tap is under consideration. It has been found that oil-in-water

emulsions used as a coal substitute fluid and stable water-in-oil emulsions used in the processing

of synthetic crude oils will lubricate when flow speed is above a critical one and other attainable

conditions are satisfied.

National Academy of Sciences- National Academy of Eng

Washington, DC 20418 $40,000

Third Annual Symposium on Frontiers of Engineering

J. R. Hunziker

With advances in engineering moving increasingly across many facets of the profession, bringing

together outstanding younger engineers from disparate fields and challenging them to think about

developments at the frontiers of areas other than their own, could have a variety of desirable

Engineering Research 37 1997
results. Such results include collaborative work, the transfer of new techniques and approaches

across fields, and the building of contacts among the next generation of engineering leaders.

This is the rationale for the Frontiers of Engineering Symposium Series.

The Third Annual Frontiers of Engineering Symposium was held September 18-20, 1997. The

meeting brought together 101 engineers (ages 30-45), 45 from academia, 45 from industry, and

11 from government labs. With primary objectives as stated above, the scope of the meeting

covered five topics: Biomechanics, Sensors and Control for Manufacturing Processes, Safety and

Security Issues, Decision-Making Tools for Design and Manufacturing, and Intelligent

Transportation Systems. The format of the meeting was to have formal presentations, typically

by two to four individuals within each subject area, followed by a substantial question-and-answer

and discussion period. Occasionally, panel discussions were employed to raise cross-cutting

issues. The dinner speech by Philip Condit, Chairman and CEO of The Boeing Company,

provided an opportunity for insights from and interaction with a highly-respected senior engineer.

The primary outcome of the meeting was the interaction it facilitated among the best young

American engineers from different fields and sectors. Attendees mentioned how rare it is to have

an opportunity, if they are academics, to talk to engineers from industry, and vice versa. They

also noted that it was enriching to learn about advances in fields other than their own, and that

they found the information useful to their own work. The meeting created the opportunity for

sharing of research insights and techniques that can spur cross-field collaboration, stimulating

leaps in engineering knowledge and applications that otherwise would take longer to achieve, if

achieved at all.

The publication that resulted from this meeting is Frontiers of Engineering: Reports on Leading

Edge Engineering from the 1997 NAE Symposium on Frontiers of Engineering. 1998.

Washington, D.C.: National Academy Press. The publication was disseminated to the

engineering and public policy community through hard copy and by posting on the Intemet.

National Academy of Sciences- National Academy of Eng

National Research Council

Washington, DC 20418 $1,130,000

Department of Energy Integrated Manufacturing Fellowship Program

T. Rozzell

Thirty-six three-year predoctoral fellowships in integrated manufacturing are in place administered

by the National Research Council, under the aegis of the National Academy of Engineering,

following national competitions. The objectives of the program are to create a pool of PhD's

trained in the integrated approach to manufacturing, to promote academic interest in the field, and

to attract talented professionals to this challenging area of engineering.

The fellowship program was conceived as one response to the loss of competitiveness of the

United States in manufacturing. Two related aspects of the problem are the traditional separation

of the product design function from the manufacturing function and the lack of an appreciation

for the process of manufacturing as an integrated system.

Engineering Research 38 1997
It is expected that the improved manufacturing methods which this fellowship aims to bring about

will contribute to improved energy efficiency, to better utilization of scarce resources, and to less

degradation of the environment.

National Aeronautics and Space Adminstration

600 Independence Avenue, S.W. $155,000

Washington, DC 20546

Center for Aerospace Research & Education for Minority Students at Southern Univ.

I. Blankson

Pursuant to an agreement between the Secretary of Energy and the Administrator of NASA, the

recommended funds will support the education of minority students at Southern University (an

HBCU) in disciplines related to aeronautics and space sciences. Over the five years of this

agreement, NASA will provide $2,500,000. The education program will be coordinated with a

research program addressing solid mechanics and finite element modeling, composite materials,

aerodynamics and impact, as well as thermal sciences (heat transfer and fluid dynamics). In

more detail examples of specific projects are Improvement of satellite rendezvous maneuvers,

optimization of gear design, analysis of the wear of diamond tools. Furthermore, these funds will

be used to strengthen the undergraduate education in aeronautics at Southern University.

National Center for Manufacturing Sciences

Technology Sourcing $0

Ann Arbor, Ml 48108

Industrial Liaison Pilot Program

J. Sheridan

The National Center for Manufacturing Sciences has been funded by DOE, Basic Energy

Sciences, to direct a progream which will place employees of the National Laboratories at

Industrial sites to work with their corporate colleagues on issues of importance to manufacturing industry. The goals of the program are to evolve expertise in a broad range of manufacturing

issues at the National laboratories, identify fundamental DOE research needs, and build a longrange sustained commitment to collaboration on industrial issues both at DOE and within

industry. Results from the Liaison Program will strengthen industry's energy efficiency in its

operations by enhancing the qulaity of the total product and developing efficient production and

management techniques. This will directly benefit American manufacturing competitiveness and

will help DOE Basic Energy Sciences identify fundamental research needs in energy efficient

industrial methodologies and technologies.

The pilot program is important. There are a number of potential risks and blockers which need

to be assessed carefully before a large commitment is made. The Industrial Liaison Program

(ILP) will place DOE laboratory workers into the industrial environment to focus the attention of

the laboratories on industry issues. The worker will remain a full time employee of the Laboratory

but the costs of the off-site per diem will be shared by the host company through a formula-based

reimbursement.

Engineering Research 39 1997
National Institute Of Standards & Technology

Electromagnetic Technology Div $120,000

Boulder, CO 80303

Low-Frequency Noise of High Temperature Superconductor/Noble-Metal Interfaces and

High-Tc Superconducting Thin Films

J. Ekin, Y. Xu

The objective of this work is to characterize the low-frequency noise behavior of

high-temperature superconductors/noble-metals interfaces, in order to provide superconducting

electronics engineers with meaningful numbers to estimate the noise magnitude for a given

interface design, and to mitigate the noise problems by better design and device fabrication

process.

We will first measure the magnitude of noise as a function of the contact area. We will also

modify the characteristics of interface conduction and study its effects on low-frequency noise.

The interface can be modified by annealing the system in oxygen, or by engineering the interface

in different crystal orientation, for example, along the c-axis direction or the ab-direction of the

YBCO thin films. We plan to use both approaches.

Since the commencement of the program in March, 1997, we have been working on assembling

the measurement system, a key element of which is a spectrum analyzer. We have also worked

intensively on oxygen annealing of YBCO/Au interface. We found that oxygen annealing

substantially reduced the contact resistivity, and changed interface transport characteristics.

Currently we are working on spectrum analyzers GPIB interface.

National Institute Of Standards & Technology

Thermophysics Division $123,000

Boulder, CO 80303

Structure and Dynamics During the Formation of Dense Silica Gels

H.J.M. Hanley

The project examines the gel structure of silica by SANS (small angle neutron scattering) and

light scattering measurements. The goal is to extend the current understanding of how gels form

on a microscopic scale, and to determine what specific changes are induced in the microscopic

structure by the influence of an applied shear. Scattered intensity data were taken on the 30 m

SANS instruments at the NIST Cold Neutron Research Facility. Samples were aqueous gels of

Ludox silica particles of nominal diameter 24 nm. The series of experiments were repeated with

the silica samples loaded into the NIST Couette shearing cell. The results showed that shear

most conclusively influences the structure of the gel. On the assumption that an investigation

of decomposition of a system to a solid would lead to an insight into the gelation mechanism, a

simulation of a two dimensional Lennard-Jones system was initiated. A striking similarity

between the computer results and the SANS data was observed. A scaling relation for the time

evolution of the structure factor of a decomposing system was proposed. SANS experiments

carried out of 7 nm silica gels have verified that the scaling relation applies to the gelling system.

Light scattering experiments on multiply scattering from the silica systems are in progress.

Engineering Research 40 1997
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National Institute Of Standards & Technology

Thermophysics Division $446,000

Gaithersburg, MD 20899

Boulder, CO 80303

Development of Measurement Capabilities for the Thermophysical Properties of

Energy-Related Fluids

R. Kayser, W. Haynes

The major objectives of this new three-year project are to develop state-of-the-art experimental

apparatus for measuring the thermophysical properties of a wide range of fluids and fluid

mixtures important to the energy, chemical, and energy-related industries. The specific

measurement capabilities to be developed are the following: Small-Volume, Dual-Cell DewBubble Point Apparatus; Heat-of-Vaporization Calorimeter and Effusion Cell for Vapor-Pressure

Determinations; Solubility Measurements Using Magnetic Levitation; Thermal Diffusivity from

Light Scattering; and Phase-Equilibria Apparatus for Azeotropic Aqueous-Organic-Salt Mixtures.

These new apparatus will extend significantly the state of the art for properties measurements

and make it possible to study a wide range of complex fluid systems (e.g., highly involatile, very

insoluble, highly polar, electrically conducting, reacting) under conditions which have been

previously inaccessible.

The City University Of New York

The City College $153,614

The Benjamin Levich Institute

for Physico-Chemical Hydrodynamics

New York, NY 10031

The Rheology of Concentrated Suspensions

A. Acrivos

This research program aims to investigate the flow of concentrated suspensions of non-colloidal

particles from the fundamental point of view. Earlier studies by the principal investigator and his

associates have shown that the rheology of such systems is strongly affected by the

shear-induced migration of particles form regions of high shear to low and from regions of high

particle concentrations to low which, by distorting the particle concentration profile, can lead to

an erroneous interpretation of the experimental measurements pertaining to the effective

viscosity of such systems. This shear-induced particle diffusion is also responsible for the

phenomenon of viscous resuspension whereby, in the presence of shear flow, a settled bed of

heavy particles can resuspend even under conditions of vanishingly small Reynolds numbers.

A theoretical model of shear-induced particle diffusion, which was developed earlier by the

principal investigator was tested experimentally in various unidirectional flows by measuring the

extent of viscous resuspension and comparing it to the theoretical predictions. Very good

agreement was found between theory and experiments even in the case of flow in a tube where

strong secondary flows are generated owing to the presence of a non-axisymmetric particle

concentration profile. Also, a technique was developed, using LDA, for measuring the particle

Engineering Research 41 1997 Engineering Research 41 1997
velocities in concentrated suspensions. This technique has been extended to measure

instantaneous 3-d particle velocities and velocity fluctuations in concentrated suspensions

undergoing a variety of shear flows in order to further test the predictions of the theoretical

model. In addition, these studies are currently being extended to bi-dispersed suspensions

involving particles of different sizes and densities.

The City University Of New York

The City College $325,798

Dept of Chemical Engineering

New York, NY 10031

Partial Control of Complex Processing Systems

R. Shinnar, . Rinard

There are two research objectives. One is to understand the control of Fluidized Catalytic

Crackers (FCC's), an important goal in itself. The second is to use the FCC as an example to

learn about the control of complex chemical plants in which the number of variables to be

maintained within acceptable limits exceeds the number of manipulatable variables available for

control. This is known as partial control.

Work finished and published this year focuses on the impact of the process design on partial

control. This was explored via the important concept of effective degrees of freedom. It was

shown for the FCC that in the simplest case of operation in partial combustion, only one degree

of freedom, the air feed to the regenerator, was required to control against changes in coking

rate. The improvements in control obtained from adding other degrees of freedom such as

catalyst recirculation rate, oil feed temperature, and heat removal using a catalyst cooler were

studied to illustrate the tradeoffs between design and control. Finally, a general approach to the

design of partial control systems was formulated.

Current work is underway in two areas. One is the exploration of the effects of model uncertainty

on the control system design, again using the FCC as an example. Second is the formalization

of the general approach and its application to control of systems and processes other than the

FCC.

The City University Of New York

The City College $123,918

The Benjamin Levich Institute

New York, NY 10031

Studies in Combustion and Explosion

G. Sivashinsky

The objective of this research program is to investigate the influence of various aerodynamical,

diffusive-thermal, radiative and reaction-rate factors on certain fundamental phenomena

associated with the combustion and explosion of gaseous premixtures. Different modeling

Engineering Research 42 1997

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techniques will be employed to reduce the study of pertinent combustion systems to simple

approximate problems tractable either analytically or numerically.

The first topic of the project concerns the problem of flame interaction with one- and multiplescale systems of eddies, and is motivated by the experimentally known phenomenon of flame

extinction by turbulence. The results obtained show that the adiabatic high Lewis number

premixed gas flame propagating through periodic vortical flow, constitutes a bistable system with

a hysteresic transition between possible combustion modes. A mildly non-adiabatic flame may

be quenced provided the flow-field intensity exceeds a certain critical level.

The second topic concerns the influence of natural conviction on the limits of thermal explosion.

The problem is of direct relevance to combustion fundamentals associated with mine and grain

silo explosions and knocks in internal combustoin engines. The explosion threshold is found to

be strongly influenced by the flow field length scale and may be raised by the small-scale stirring

and lowered by the large-scale one, compared to the case of stagnant premixture.

The third topic concerns the classical problem of the deflagration-to-detonation transition in pipes

and dusted gases. The preliminary analysis based on a reduced reaction-diffusion-acoustics

model showed that the transition is largely controlled by the friction-induced momentum losses,

ignored in the previous attempts to describe the phenomenon. At sufficiently strong friction the

normal Chapman-Jouget type detonation is found to undergo a jumpwise hysteresic transition

to a low speed quasi-detonation dominated by dissipative effects.

State University Of New York

Department of Physics $196,126

Stony Brook, NY 11794

Sub-Electron Transfer of Electric Charge in Semiconductor Nanostructures

K.K. Likharev

The goal of the project is to find the crossover between the continuous and discrete transfer of

electric charge transfer in semiconductor nanostructures. Understanding of this crossover is of

the key importance for the future development of nanoscale electronic devices. As a result of

the theoretical effort during the first two years of the project, the charge discreteness has been

calculated for three important models of nanostructures. The analysis has shown that the charge

continuity cannot be provided by the electrostatic screening alone; another key condition is the

smallness of the electron energy relaxation distance in comparison with the sample length.

Experimental techniques to measure the charge discreteness via the intensity of non-equilibrium

fluctuations in nanostructures have been developed. Initial measurements of the fluctuations

have been carried out for p-doped channels of SiGe MESFETs and MOSFETs, with gates

typically 30 um wide and 5 um long, at temperatures from 4 to 300 K. To circumvent the 1/f noise

which was dominant in first experiments, the experimental set-up is being extended to the 1-GHz

frequency range.

Engineering Research 43 1997
Northwestern University

Engineering & Applied Science $0

Evanston, IL 60208

Thin-Film Characterization and Flaw Detection

J. Achenbach

This work is concerned with the determination of the elastic constants of thin films deposited on

substrates, with the measurement of residual stresses in such films and with the detection and

characterization of defects in thin film substrate configurations.

There are many present and potential applications of configurations consisting of a thin film

deposited on a substrate. Thin films that are deposited to improve the hardness and/or the

thermal properties of surfaces are of principal interest in this work. Thin film technology does,

however, also include high Tc superconductor films, films for magnetic recording, superlattices

and films for band-gap engineering and quantum devices. The studies carried out on this project

also have relevance to those applications.

Both the film and the substrate are generally anisotropic. A line-focus acoustic microscope, is

being used to measure the speed of wave modes in the thin film/substrate system. This

microscope has unique advantages for measurements in anisotropic media. Analytical and

numerical techniques are employed to extract the desired information on the thin film from the

measured data. Recent results include: (1) use of multiple wave modes to determine thin film

constants, (2) measurements of superlattice film constants, and (3) investigation of the effect

of surface roughness.

Northwestern University

Dept of Chemical Engineering $140,255

Evanston, IL 60208

Theory of Subcooled Boiling

S. Bankoff, S. Davis

Subcooled boiling is perhaps the most efficient means of steady high-heat-flux transfer from solid

surfaces, such as in rocket motors and heat treatment of metals. The growth and collapse of

small bubbles while attached to the heating surface will be studied analytically and numerically.

When the critical heat flux is exceeded, subcooled film boiling results. The stability of the

resulting vapor film, involving momentary contacts or evaporating liquid tongues with the hot solid

wall, and the criteria for growth of these contacts determine the minimum film boiling

temperature. To begin with, two problems have been considered. The first paper deals with a

circular, evaporating liquid wedge, which oscillates in radius, on a hot horizontal plate. This

simulates the periodic dryout and rewetting by a thin liquid film under a growing-and-collapsing

bubble in subcooled nucleate boiling. The second problem has led to a long-wave evolution

equation for a thin vapor film on a horizontal heated plate, in subcooled film boiling. Linear

stability results when an evaporation number, E, exceeds a critical value, Ec. When E<Ec, a

pitchfork bifurcation is found, and a new evolution branch is found. Work is continuing on both

of these problems.

Engineering Research 1997

44
Northwestern University

Dept of Eng Sci & App Math $64,114

Evanston, IL 60208

Complex Interfacial Flows

M. Miksis

The research here in the first year of this grant will be directed into two areas. The first concerns

the spreading of a liquid along the interface of a second liquid. Here we will be concerned with

the stability and dynamics of the liquid interfaces. In particular, we will address the question of

how the physical parameters in this problem influence the spreading. Second we will be

concerned with the dynamics of foams. This study will build on our current work on modeling the

microscopic behavior of foam flow in porous media and on the dynamics of thin films. Both of

these problems are directly related to the clean up on both land and water of hazardous waste

spills and enhanced oil recovery.

Northwestern University

Dept of Chemical Engineering $155,219

Evanston, IL 60208-3120

Fragmentation and Dispersion of Powdered Solids in Viscous Liquids

J. Ottino

Mixing processes are ubiquitous in industry. Our aim is conduct broad-based basic work in the

area of mixing with the goal of producing useful knowledge to wide array of users. Work may

be divided into Mixing of Viscous Liquids and Powdered Solids and Mixing of Powders.

Substantial progress has been made on all fronts. Computational studies have been completed

in the area of aggregation in regular and chaotic flows [1]. Work on fragmentation - including

erosion -- has been completed as well [2]. We have also made substantial progress in the

development of a model dealing with liquid-liquid mixing processes involving drop breakup and

coalescence [3]. Work carried under The Mixing of Solids heading, initially perceived as an

extension of on our work in suspensions, is quickly becoming a large and distinct area.

Substantial progress has been made in this area as well, particularly for the case of non-cohesive

materials. We have shown that slow mixing processes can be modeled as a succession of

avalanches and .that processes can be divided into geometrical and dynamical parts. In depth

aspects of dynamical aspects -- leading for example to segregation effects -- can be incorporated

by means of molecular dynamic simulations.

[1] S. Hansen and J.M. Ottino, Aggregation and Cluster Size Evolution in Non-Homogenous

Flows, J. Colloid and Int. Sci., 179, 89-103 (1996).

[2] S. Hansen and J.M. Ottino, Agglomerate Erosion: A Non-Scaling Solution to the

Fragmentation Equation, Phys. Rev. E, 53, 4209-4212, 1996; S. Hansen and J.M. Ottino,

Fragmentation with Abrasion and Cleavage: Analytical Results, Powder Tech. (1997), to appear.

1Engineering Research 1997

Engineering Research 45 1997
[3] J. M. Ottino, P. de Rousell, S. Hansen, and D.V. Khakhar, Mixing and Dispersion of

Viscous Fluids and Powdered Solids, Advances in Chemical Engineering submitted (1997).

[4] D.V. Khakhar, J.J. McCarthy, T. Shinbrot, and J.M. Ottino, Transverse Flow and Mixing of

Granular Materials in A Rotating Cylinder, Phys. Fluids, 9, 31-43 (1997).

Northwestern University

Dept of Eng Sci & App Math $69,954

Evanston, IL 60208

Stability and Dynamics of Spatio-Temporal Structures

H. Riecke

The objective of this project is to contribute to the understanding of the dynamics of spatial

structures and of spatio-temporal chaos as they arise in physical systems ranging from flows in

fluids and in granular media to lasers and coupled oscillators.

This task is approached by investigating paradigmatic cases that address fundamental and

applied issues. Fundamental aspects to be investigated in particular are the characterization and

classification of states that are disordered in space and time, and the possible mechanisms for

the localization of structures in space. These studies are expected to be important also for

applications. For instance, in wide-area lasers spatio-temporal chaos can reduce the quality of

the laser beam and can even be detrimental to the device itself. To address such problems a

detailed understanding of the origin and the nature of the chaotic state is necessary.

Using analytical and numerical techniques, a number of paradigmatic systems have been

investigated. Convection driven by surface tension is important in materials processing; the

stability of surface-tension-driven convection has been studied in detail. The effect of a

simultaneous breaking of spatial and temporal symmetries has been investigated in a joint

experimental/theoretical effort in fluid flow between rotating cylinders. Substantial progress has

been made in the understanding of the stability of waves in anisotropic systems, e.g. in

liquid-crystal convection.

Current studies of simple models investigate the possible mechanisms that are responsible for

the localization of wave structures in periodically shaken granular media and the interaction

between those structures ('oscillons'). The studies of spatio-temporal chaos focus now on a

transition between ordered and disordered defect chaos in parametrically driven waves.

Engineering Research 46 1997 Engineering Research 46 1997
University Of Notre Dame

Dept of Chemical Engineering $79,873

Notre Dame, IN 46556

Fundamental Study of Long-Short Interfacial Wave Interactions and Application to Flow

Regime Development

M.J. McCready

Knowledge of flow regime is the most important issue in the design and operation of multiphase

flow pipelines. Growth of interfacial waves that are long compared to the depths of the two

phases is known to play an important role in regime transition from a stratified gas-liquid flow.

Current procedures for predicting regime transitions use linear instability of one-dimensional

momentum equations as a transition criterion. However, recent work has shown that the

predictions of one-dimensional equations differ significantly from the full differential equations

and further, that the development process of long wave disturbances is nonlinear.

In this project experiments and theory are being used to discover the flow parameters that control

the growth rate of long wave disturbances. To allow for accurate comparison to theory, the

system under study is a light hydrocarbon oil - water flow in a wide rectangular channel oriented

close to horizontal. The long-wave -- short-wave interactions that occur in these systems and

can cause accelerated growth of long waves are being examined. Slight variations of the flow

angle from horizontal allow a wide variation in the relative growth rates and speeds of long and

short waves. Theory employs weakly-nonlinear simplifications of the complete Navier-Stokes

equations and boundary conditions.

Oak Ridge National Laboratory

Engineering Physics $1,528,000

and Mathematics Division

Oak Ridge, TN 37831

Center for Engineering Systems Advanced Research (CESAR)

J. Barhen, H. K. Liu, L. Maya, N. Peterfreund, E. Oblow, L. Parker, V. Protopopescu,

N. Rao, D. Reister

The primary mission of the Center for Engineering Systems Advanced Research (CESAR) is to

develop, through innovative basic research, a core of excellence in intelligent systems

technology. By combining long-range future-oriented R&D efforts with near-term, sustained

technology transfer to U.S. industry, and with undergraduate, graduate, and post-graduate

student training, CESAR strives to enhance U.S. scientific and technological capabilities in

strategic areas vital to energy independence, national security, and global competitiveness.

Currently, CESAR's efforts emphasize two basic research thrusts: computational nonlinear

science and cooperating autonomous systems. The latter are characterized as systems that

integrate perception, reasoning, and action to perform tasks under circumstances that are either

insufficiently known in advance or dynamically change during task execution. Perception,

reasoning, and action, as well as the integration of these modules into prototype working

systems, present outstanding challenges for inter-disciplinary basic research. The CESAR

Engineering Research 47 1997
e u

approach focuses the effort on high-priority research topics, such as multiple cooperating agents,

multisensor fusion, and machine learing, and scopes the research activities so that integrated

proof-of-principle experiments with the CESAR robot testbeds can be performed. Experimental

paradigms include exploration and map-building using sonar and vision sensing, navigation in

changing environments, and cooperative observation of multiple moving targets. Additional

scenarios will include reliable 3-D world modeling based on laser range, sonar, vision, and novel

hyperspectral sensors; and integration of high-level intelligent control with low-level reactivity

behavior in robot architectures. In the area of computational nonlinear science, the main

emphasis of the CESAR thrust is on developing innovative mathematical and computational tools

to successfully address the selected "Grand Challenges". The proposed effort builds upon

CESAR's unique advances in neural network learning, global optimization, solving inverse

problems by optimal control techniques, and fusion rule estimation using empirical data.

Promising new directions also being explored include quantum control of nanotechnology

systems, as well as the emerging paradigms of optical and nanoelectronic- computing and

information processing.

Technology transfer of CESAR innovations is rapidly growing, particularly to the automotive and

petroleum exploration industries.

Oregon State University

Department of Mechanical Engineering $70,174

Corvallis, OR 97331

Phase Change Phenomena in Enclosed Microstructures with Forced Flow

J.R. Welty

This is a collaborative research effort involving Oregon state University and the Pacific Northwest

National Laboratory in Richland, Washington. The objectives are the following:

1. To delineate how transport phenomena in microchannels differ from their macroscale

counterparts. An understanding of, and ability to describe and predict behavior, is essential for

the design of effective and efficient miniature thermal and chemical systems.

2. To investigate flow behavior within microchannels with widths of 100 microns and smaller

under both isothermal and non-isothermal conditions with both single-phase (liquid) and

two-phase (liquid-vapor) conditions present.

3. To understand and capture phase change phenomena along with dominant flow regimes in

rectangular microchannels of various aspect ratios.

The experimental component of this effort involves using Particle Image Velocimetry (PIV) and

Laser Induced Fluorescence (LIF) to obtain both a qualitative understanding of phase change

phenomena and a quantitative understanding of the relationship between geometric

characteristics, flow characteristics, imposed heat flux, and the attainable heat transfer and

pressure drop. The simulation component involves the development and adaptation of

Lattice-Boltzmann approaches to model both hydrodynamics and energy exchange in rectangular

microchannels.

Engineering Research 48 1997 Engineering Research 48 1997
Pennsylvania State University

Mechanical Engineering Dept $98,598

University Park, PA 16802

Research on Combustion-Driven HVOF Thermal Sprays

G. Settles

The High-Velocity Oxy-Fuel (HVOF) thermal spray process combines the fields of materials,

combustion, and gas dynamics. It relies on combustion to melt and propel solid particles at high

speeds onto a surface to be coated. The goal of this research is to understand and improve the

HVOF deposition of corrosion-resistant coatings, which are important in many energy-related

industries.

HVOF spraygun nozzle design and operating parameters have been found with which to vary the

kinetic and thermal energies of the spray particles independently. For example, for sprayed

coatings of 44 micron 316 Stainless Steel powder, the in-flight particle temperature is varied from

1600-2300K and the particle speed is varied from 250-450 m/s. Through metallographic

analysis, the resulting coating properties are seen to range from dense, high-quality coatings (low

temperature, high speed) to oxide-bearing coatings of questionable utility (high temperature, low

speed). The ability to tailor coatings to produce desirable properties, and knowledge of the wide

range of coating properties possible from a given metallic powder, are important to the thermal

spray field. Experiments and modeling using a broader range of sprayed materials are planned.

Princeton University

Dept of Mech & Aero Eng $44,210

Princeton, NJ 08544

Unification of Stretched Flame Phenomena

C. Law

The thermal structure of counterflow premixed and diffusion flames was experimentally and

computationally determined to examine the response of flame structure to strain rate and

pressure variations. For both near-equidiffusive and nonequidiffusive premixed flames, results

show that variation of the thermal structures is much smaller than that of the strain rate, while

the structural sensitivity also decreases with increasing pressure. For diffusion flames, results

show that the flame structure at different pressures largely scale with the density-weighted strain

rate. It is further demonstrated that stretch effects can be predicted with good accuracy by

knowing the laminar flame speeds of the one-dimensional planar flame as a function of the

system pressure and equivalence ratio.

The passive propagation of wrinkled, non-folding, premixed flames in quiescent and spatially

periodic flow fields was investigated by employing the scalar field, G-equation, formulation. For

the stretch-affected flame propagation mode, the resulting G-equation is in the general form of

the Burgers' equation. Analytical solutions were obtained for several flame and flow types,

describing the formation of cusps and their inner structure, and the augmentation of the average

burning velocity through flame wrinkling.

Engineering Research 49 1997

Engineering Research 49 1997
Princeton University

Dept of Civil Engineering $125,331

Princeton, NJ 08544

Transport Properties of Disordered Porous Media From The Microstructure

S. Torquato

This research program is concerned with the quantitative relationship between transport

properties of a disordered heterogeneous medium that arise in various energy-related problems

(e.g., thermal or electrical conductivity, trapping rate, and the fluid permeability) and its

microstructure. In particular, we shall focus our attention on studying the effect of: porosity,

spatial distribution of the phase elements, interfacial surface statistics, anisotropy, and size

distribution of the phase elements, on the effective properties of models of both unconsolidated

media (e.g., soils and packed beds of discrete particles) and consolidated media (e.g.,

sandstones and sintered materials).

Both theoretical, computer-simulation, and experimental techniques have been employed to

quantitatively characterize the microstructure and compute the transport properties of disordered

media. Statistical-mechanical theory has been used to obtain n-point distribution functions and

to study percolation phenomena in continuum random-media models. For example, the pore-size

distribution, lineal path function, and the chord-length distribution function have been investigated

and computed. This has led to accurate predictions of transport properties of realistic models

of isotropic as well as anisotropic heterogeneous media. Cross property relations have been

derived. Rigorous relations which link the fluid permeability to length scales obtainable from

Nuclear Magnetic Resonance experiments and the effective electrical conductivity have been

derived. Moreover, the effective conductivity has been related to the effective elastic moduli.

Recently, 3-D images of a sandstone have been obtained using x-ray tomographic techniques

and statistical correlation functions have been extracted from them. Recently, we have made

progress on the inverse problem of reconstructing the structure of porous media from lower-order

correlation functions.

Purdue University

School of Nuclear Engineering $0

West Lafayette, IN 47907

Interfacial Area and Interfacial Transfer in Two-Phase Flow

M. Ishii

The objective of the research program is to develop instrumentation methods, experimental data

base and models for describing the interfacial structure and behaviors of two-phase flows. In

terms of the flow structure, the transverse distributions of the local void fraction, interfacial area

concentration, fluid particle size and their axial development from the entrance to the exit will be

the primary focal point of the experimental research. For the purpose of understanding the

dynamic behaviors, the interfacial velocity, fluid particle coalescence and disintegration are

studied. The axial changes in the distribution of void fraction and interfacial area give the

information on the particle coalescence and disintegration. These are used to quantify the flow

Engineering Research 50 1997

Engineering Research 50 1997
regime transitions. The multi-sensor probes are used together with hot-film probes for these

measurements. The focus of the modeling effort is to develop an interfacial area transport

equation which incorporates the mechanistic models for coalescence and disintegration of fluid

particles. This transport equation describes dynamical change of the interfacial structure and

replaces the conventional model based on flow regime transition criteria.

Purdue University

School of Mechanical Engineering $124,419

West Lafayette, IN 47907

Critical Heat Flux in Micro-Channel Flow

I. Mudawar

This project targets the development of a theoretical model for critical heat flux (CHF) from long

heated walls in vertical flow. Flow boiling pattern is examined with the aid of photomicrographic

and high-speed video imaging techniques in order to determine the CHF trigger mechanism.

Close-up studies of the wall region have revealed features common to most bulk flow conditions.

At fluxes below CHF, the vapor coalesces into a wavy layer which permits wetting only in wetting

fronts, portions of the liquid-vapor interface which contract the wall as a result of the interfacial

waviness. These waves are generated from the heater's upstream region with wavelengths

following predictions based upon the Kelvin-Helmholtz instability criterion. Critical heat flux

occurs when the pressure force exerted upon the interface due to interfacial curvature, which

preserves interfacial contact with the wall prior to CHF, is overcome by the momentum of vapor

at the site of the first wetting front, causing the interface to lift away from the wall. Recent

studies have shown this interfacial lift-off criterion facilitates accurate theoretical modeling of CHF

in both straight and curved channels. Present studies are focused on extending this model to

highly subcooled conditions.

Rensselaer Polytechnic Institute

Dept of Mechanical Engineering, $149,535

Aeronautical Eng & Mechanics

Troy, NY 12180-3590

Inelastic Constitutive Equation: Deformation Induced Anistropy and the Behavior at

High Homologous Temperature

E. Krempl

Using experimental results obtained with computer-controlled, servohydraulic testing machines,

continuum mechanics and materials science as backgrounds, constitutive equations

(mathematical models of material deformation behavior that are used in stress and life-time

analyses) are being developed with emphasis on two aspects: Deformation induced anisotropy

for large deformation on the one hand and high homologous temperature on the other. Both

areas extend the modeling capability of the previously developed "unified," state variable

viscoplasticity theory based on overstress (VBO).

Engineering Research 51 1997
A mathematical framework and a formulation for the representation of deformation induced

anisotropy has been developed that includes the effects of texture. For large inelastic

deformation an isotropic metal or alloy can be deformed into metal or alloy with elastic and

inelastic anisotropy that depends on the deformation path. The compliance matrices are allowed

to change according to an anisotropic Frederick-Armstrong growth law. Representations for initial

isotropy and orthotropy have been found. Simulations of deformation induced anisotropy are

underway.

The small strain version of VBO has been extended to high homologous temperature and applied

to Alloy 600 H at homologous temperatures above 0.7. The model can simulate the

experimentally observed creep and tensile behavior. It is also shown that the transition from the

solid to the fluid state can be accomplished easily with VBO. It has also been applied to the

modeling of solder alloys that operate high homologous temperature in the vicinity of ambient

temperature. Creep and rate-dependent stress-strain behaviors were simulated well with VBO

that had the minimum number of constants possible. This minimalist theory is also capable of

modeling the Alloy 800H data that had previously been modeled with a version that had twice as

many constants as the simplified version.

It was found that VBO could be modified easily to represent inverse rate sensitivity. This

capability opens the door to the modeling of strain aging behavior that is found in most

engineering alloys at some range of temperature.

Rensselaer Polytechnic Institute

Dept of Chemical Engineering $ 0

Troy, NY 12180-3590

Development and Use of Image Scanning Ellipsometer to Study the Dynamics of Heated

Thin Liquid Films

P. Wayner, Jr., J. Plawsky

The physicochemical phenomena associated with fluid flow, change-of-phase heat transfer, and

drying in ultra-thin (thickness less than 10-5 m) aerogel and liquid films are being studied. In the

thin liquid film systems, the interfacial, intermolecular, force field, which controls fluid flow and

heat transfer, is a function of the film thickness profile. If the physical properties of the

evaporating liquid film are known, the film thickness profile, measured experimentally, can be

used to calculate the pressure field and the local evaporative heat transfer rate. To measure the

film thickness profile, a novel ellipsometric technique (Image Scanning Ellipsometry, ISE) has

been developed. ISE combines classical null ellipsometry with microscopic image processing,

to determine simultaneously the thickness of the liquid film at all points on the substrate. Image

processing helps identify the precise location on the surface of the liquid film which corresponds

to the measured thickness. Thus a 2-D profile of the liquid film can be constructed. A second

generation ISE employing enhanced resolution image acquisition and processing equipment has

been constructed. The augmented processing power of the second generation instrument is

expected to help plot more precise thickness profiles. Results obtainedusing the initial design

were presented in Applied Optics, 33, pp 1223-1229, 1994, and, Physics Fluids, 6, pp 1963-

1971, 1994. Presently, the formation of thin aerogel films is being emphasized. The role of

process parameters in the ambient drying proces, such as extent of silylation, aging time, pH,

and drying temperature, on the final film properties are being studied.

Engineering Research 52 1997

Engineering Research 52 1997
Rice University

Dept of Civil Engineering $93,360

Houston, TX 77251

A Novel Nonlinear System Identification Approach with Applicability to Aging of Energy

Production and Distribution Systems

P. Spanos

Nonlinear forces acting on energy systems such as large offshore structures, are studied from

a perspective of system identification. The nonlinearities may be induced by ocean waves, and

they may become significant in several situations. They are not necessarily assumed to be in

the form of Morison's equation. Various wave forces are examined. The force function is

decomposed either into a set of base functions, or it is expanded in terms of the wave and

structural kinematics. The resulting nonlinear system is decomposed in a number of parallel nonmemory, nonlinear systems, each followed by a finite memory subsystem. A Gram-Schmidt

orthonormalization procedure is applied to decouple these subsystems; a frequency domain

technique involving auto-spectra and cross-spectra is employed to identify the linear transfer

function. In conjunction with this problem, an efficient algorithm for representing random

processes by auto-regressive-moving-average digital algorithms is pursued for implementation

into system identification problems. The analytical results are calibrated by Monte Carlo

simulation studies.

University Of Rochester

Dept of Physics and Astronomy $74,090

Rochester, NY 14627

Flux Flow, Pinning, and Resistive Behavior in Superconducting Networks

S. Teitel

Vortex fluctuations play a dominant role in determining the phenomenological behavior of high

temperature superconductors. In particular they are a major source of electrical resistance when

an external magnetic field is applied.

Theoretical understanding of the effects of vortex fluctuations is therefore a key step in the

technological application of the high temperature superconductors.

The system of many strongly interacting vortices, coupled to random material impurities, is a

complex many-body statistical problem. To deal with this complexity, large scale numerical

simulations are used to study behavior as temperature, applied magnetic field, material

anisotropy, and random disorder are varied.

Recent efforts have focused on the behavior of three dimensional vortex lines in bulk

superconductors, where a vortex line lattice forms at low temperature. Simulations indicate that

for a finite temperature region above the vortex lattice melting temperature, the energy barrier

for vortex line cutting is significant. The width of this region shrinks as the material

anisotropyincreases. Such barriers to cutting can have a significant effect on vortex line

diffusion, and hence flux flow resistance. New simulations are extending earlier equilibrium work

to study non-equilibrium steady state dynamics, and to include the effects of random impurities.

Engineering Research 53 1997
University Of Rochester

Dept of Physics and Astronomy $99,002

Rochester, NY 14627

Direct and Inverse Problems in Statistical Wavefields

E. Wolf

This research is chiefly concerned with determining the structure of fluctuating sources and also

of scattering objects whose physical properties are random functions of position, from

measurements of radiated and scattered fields. We have derived a new conservation law for

fields generated by random, statistically stationary scalar sources of any state of coherence and

we analyzed some of its implications on the phenomenon of correlation-induced spectral

changes. We have extended the theory of diffraction tomography to make it possible to

determine the degree of spatial correlation of a scattering potential of a random object from

measurements of the crossspectral density of the scattered field in two planes, one on each side

of the scatterer. We have also formulated a generalization of the optical crosssection theorem

which in its usual form makes it possible to determine the scattering crosssection from the

knowledge of the forward scattering amplitude. The generalization extends the theorem to

situations where the incident field or the scatterer or both must be described statistically. We

showed how the generalized theorem can be used to determine the structure of some random

scatterers.

The Rockefeller University

Department of Physics $201,152

1230 York Avenue

New York, NY 10021

Some Basic Research Problems Related to Energy

E. Cohen

1. A very simple interpolation formula for the Newtonian viscosity as well as the visco-elastic

behavior of monodisperse hard sphere colloidal suspensions has been derived theoretically for

low as well as high concentrations. The formula has been adapted to micelles and is being tested

for polymers. An extension to shear-rate dependent effects is in progress.

2. The investigation of Lorentz lattice gas cellular automata is continued. In this gas a point

particle moves on the bonds of a lattice fully or partially occupied by deterministic scatterers of

two types, which scatter the particle either to its left or to its right and change their scattering

character after collision with the particle. Complex diffusion-propagation patterns of motion of the

particle then emerge. This complex behavior of a very simple system could well be the prototype

for a variety of phenomena found in nature. This is further investigated.

3. Dynamical weights using expanding Lyapunov exponents, rather than the usual probabilistic

(Gibbsian) weights, can be employed to obtain the probability distribution of a many particle

system in a nonequilibrium stationary state (e.g. a sheared fluid), which can be far from

equilibrium. Successful applications of this new approach to obtain the properties of such a

system have been made and are further pursued.

Engineering Research 54 1997
I I

Sandia National Laboratories

Combustion Research Facility $150,000

Thermofluids Division

Livermore, CA 94550

Dynamically Active Scalars in Turbulent Combustion, Heat Transfer, and Geophysical

Flows

A. Kerstein

The principal focus of this research program is modeling of turbulent flows in which mixing

modifies flow energetics, as in buoyant stratified turbulence and turbulent combustion. Turbulent

motions are represented by mappings applied to a one-dimensional domain on which a velocity

profile, and profiles of participating scalar quantities, are defined. The mappings are determined

by turbulence energetics based on local shear and any dynamically active scalars. The

mappings modify the velocity and scalar profiles, yielding a self-contained evolution process

involving minimal empiricism.

Molecular transport (viscosity and species diffusion) are implemented concurrently with the

mapping process in this fully resolved formulation. Models lacking full spatial resolution do not

reflect the distinct roles of advection and molecular transport.

This formulation, denoted One-Dimensional Turbulence, has been applied to various

constant-density and variable-density flows. The model reproduces key features of the turbulent

cascade and the spatial structure (mean and fluctuation properties) of inhomogeneous

shear-driven and buoyancy-driven flows.

Ongoing work focuses on flows of particular engineering and geophysical relevance. Salient

topics include mixed-convection heat transfer, contaminant dispersion in the atmospheric

boundary layer, and layering in double-diffusive convection.

Science Applications Intl Corp

Biotechnology Research and 149,940

Applications Group

McLean, VA 22102

Function-Based Biosensors for Use in Hazardous Waste Remediation

J. J. Hickman

Research Objectives and Scientific Approach

The goal of this work is to develop a new type of sensor capable of detecting toxins in hazardous

waste effluents after remediation. This novel biosensor will monitor the changes in electrical

signal between two neurons adhered to a uniquely patterned artificial surface in a defined growth

media. The changes in electrical signal will correspond to the changes in neuron-neuron

communication upon the introduction of a toxin. This type of sensor would be able to sense

known as well as unknown toxins in hazardous waste effluents after remediation.

Engineering Research 55 1997
Current Status of Project

Great progress has been made in several key areas via the commitment of SAIC internal

research and development funds to jump-start and augment this program during the first year.

Initial screening established extreme cases of self-assembled monolayer (SAM) modified

surfaces which would either promote or impede neuronal growth on the substrates. These

SAM's were then used to construct lithographically defined surface for neuronal patterning. A

key area of progress was to establish a laser system that gave reproducible patterns. The

collaborative effort with NIH, NINDS has allowed the culture and electrophysiological

characterization of rat hippocampal neurons on these high resolution patterned surfaces in

defined media.

Preliminary cell culture results have indicated we have extended the longevity and fidelity on the

pattems. We have applied new surface analysis tools in these investigations that have enabled

a clearer understanding of the relationship between surface and cell response. In the second

year of the project the primary goal will be extension of the in vitro culture system on the patterns

to > 1 month. Preliminary response of the rudimentary circuits to toxins will also be investigated.

Finally, the initial solid-state system will be designed.

Stanford University

Dept of Mechanical Engineering $140,455

Stanford, CA 94305-3030

Stress and Stability Analysis of Surface Morphology of Elastic and Piezoelectric

Materials

H. Gao, D. Barnett

The objective of this research has been to study morphological stabilities and instabilitites in

elastic and piezoelectric solids. In morphologies are included surface shapes, cracks, and defect

patters. In the past year, we have developed techniques to study electrical nonlinearity near

cracks in piezoelectric ceramics, and to study equilibrium and dynamic 2-dimensional

arrangements of large numbers of dislocations.

Recent experimental observations of the cracking behavior of piezoelectric ceramics under

combined electrical and mechanical loads contradict predictions made by the existing linear

piezoelectric fracture theory. Evidently, a fracture criterion suitable for piezoelectrics must

account for material nonlinearity. We identify a region of electrical nonlinearity near the crack tip

in which the mechanical response of the material remains linear. For closed-form solutions, we

adopt the Dugdale approximation by restricting nonlinear effects to a strip zone ahead of the

crack tip. The energy release rate derived using this model agrees qualitatively with empirical

measurements of electromechanical fracture load. A remarkable feature of our model is that the

energy release rate is strictly independent of the form of the nonlinear electrical constitutive

relation. The material may even experience domain switching in the Dugdale zone without

affecting the fracture criterion determined by our formulation. We are presently implementing

nonlinear finite element algorithms to verify and extend the predictive capability of our analytical

models.

Engineering Research 56 1997
* U

Patterns of both equilibrium and dynamic 2-dimensional arrangements of large numbers of

dislocations have been computed numerically. In the case of equilibrium arrangements

minimization of the total potential energy of the stressed and dislocated solid is performed; the

dynamic studies are accomplished by forward integration of the non-linear stress-dislocation

velocity relation. Both types of studies normally would require numerical computations of order

N2, where N is the total number of dislocations. We have extended the fast-multipole method

to treat doubly periodic arrangements of dislocations, so that (1) simulations of large numbers

of dislocations are easily accomplished with a method that is O(N), (2) the effects of elastic

anisotropy may be included, and (3) the advantage of a fast multipole method with exponentially

decaying multipole contributions can be utilized. We are presently studying the kinetic formation

of dislocation cell structures and intend to pursue studies or arrangements of 3-dimensional

dislocation loops during the coming year.

Stanford University

Edward L. Ginzton Laboratory $231,000

Stanford, CA 94305-3030

Optical Techniques for Characterization of High Temperature Superconductors

G. Kino

The aim of this program is to use photothermal techniques to measure the normal carrier density

below the transition temperature Tc in hightemperature superconductors, to study the nature of

the phase transition and to measure the homogeneity and quality of these materials. A modulated

focused laser beam incident on the sample varies its temperature periodically, and a second

probe beam a few microns away measures the differential reflectivity (dR/dT) associated with

the thermal wave propagating along the sample. Changes in critical temperature in regions less

than 100microns apart have been measured, and the difference in quality of different samples

can clearly be seen. Measurement of thermal diffusivity in single YBCO crystals yields good

estimates of the variation of normal electron density with temperature. Polarized light

observations of single-crystal YBCO near the transition point yield curves as a function of

temperature with shapes that are very different depending on the polarization of the probe beam

relative to the A and B directions. The nature of the transitions near the critical temperature

varies radically with wavelength in the range from 1.3 microns to 0.633 microns.

Stanford University

Mechanical Engineering Dept $235,764

Stanford, CA 94305

Nonequilibrium Plasma Chemistry

C. Kruger, T. Owano

This research is concemed with optical diagnostics for plasma chemistry and plasma processing,

with an emphasis on methods that allow for departures from local thermodynamic equilibrium

(such as finite chemical reaction rates, nonequilibrium electron densities and temperatures, and

radiation loss effects). Studies in an induction plasma facility show significant nonequilibrium

Engineering Research 7 1997

Engineering Research 571997
within a downstream reactor, and suggest the possibility of erroneous results when using

conventional diagnostics that assume local thermodynamic equilibrium.

Advanced laser-based methods are being developed for measurement of plasma parameters

including species concentration and temperature. The primary techniques under investigation

are Degenerate Four-Wave Mixing (DFWM) and Cavity Ring-Down Spectroscopy (CRDS).

These techniques are being applied to atmospheric pressure and near-atmospheric pressure

plasma environments in order to assess the importance of nonequilibrium effects under

conditions of interest to plasma chemistry.

Experiments using DFWM to probe CH and C2 within the reacting plasma have demonstrated

the ability to provide sensitive (ppm level) detection with submillimeter spatial resolution in the

measurement of vibrational temperatures, rotational temperatures, and species concentrations.

The use of CRDS to detect CH3 radicals with high sensitivity and high spatial resolution has also

been recently demonstrated.

Stanford University

Dept of Chemistry $ 0

Stanford, CA 94305

Topics in a Thermodynamic and Stochastic Theory of Nonlinear Processes Far from

Equilibrium

J. Ross

Research focuses on the thermodynamic and stochastic theory of hydrodynamic processes, such

as combinations of chemical reactions, diffusion, thermal conduction, and viscous flow. Such

theories have been formulated for each of the individual processes, both linear and nonlinear.

Progress has been made exemplified by: a stochastic approach to nonequilibrium chain

reactions in disordered systems: Breakdown of eikonal approximation; a study to show that an

endogenous calcium oscillator may control early embryonic division; research on deterministic

and stochastic asymptotic behavior for nonequilibrium chemical systems with time-dependent

rate coefficients; the use of a stochastic potential for a periodically forced nonlinear oscillator;

and fluctuation dynamics, thermodynamic analogies and ergodic behavior for nonequilibrium

independent rate processes with dynamical disorder; and to show the role of Liapunov functions

in the issues of stability and relative stability in reaction diffusion systems with multiple stationary

states. This theory has also been extended to study fluctuations near limit cycles in chemical

reaction systems. An extensive analysis has been published on the categorization of some

oscillatory enzymatic reactions. Prior measurements on glygolytic metabolites by capillary zone

electrophoresis have been used for steady-state measurements on the fructose

6-phosphate/fructose 1,6-biophosphate interconverison cycle.

Engineering Research 58 1997
U U

Stanford University

Dept of Chemistry $95,110

Stanford, CA 94305

Laser-Based Diagnostics for Plasma Chemistry

R. Zare

We have used Cavity Ring-Down Spectroscopy (CRDS) to measure near-infrared overtone

transitions of water in atmospheric flames (propane premixed jet and laminar methane-air flat

flame burner). CRDS allows more than ten thousand round trips in a high finesse cavity which

results in high sensitivity (108 cm-

') to absorbers in the cell. Moreover, signal output with a welldefined laser beam direction, and the insensitivity of CRDS to a strong emission background

present in hostile environments, make CRDS ideal for the study of combustion environments.

We have obtained spectra of water vapor from within a flame without significant backgrounds,

and have extracted from these spectra the rotational temperature of water vapor as a function

of distance from the plane burner surface. These results are in excellent agreement with both

simulations and previous experiments reported in the literature.

University Of Texas At Austin

Center for Studies in Statistical Mech $220,001

and Complex Systems

Austin, TX 78712

The Extended Formulation of Dynamics and Computational Tools for Complex Systems

I. Prigogine, T. Petrosky, L. Riechl

Over the last year a number of successful applications of our new formulation of dynamics (i.e.

our probabilistic extension of dynamics outside the Hilbert space, which incorporates

time-symmetry breaking and is irreducible to trajectories or wavefunctions) were obtained. They

include the mechanism of the breakdown of integrability of a soluble quantum system (a

one-dimensional gas with delta-function interactions) in the thermodynamic limit, as well as

kinetic theory of moderately dense classical gas. In the former, it was shown that the

nonintegrability invalidates a fundamental principle of quantum mechanics, the "Ritz-Rydberg

principle" according to which each frequency has a difference between two energy levels. Indeed

it was shown that the eigenvalues of the Liouville-von Neumann operator were not differences

of eigenvalues of the Hamiltonian in the thermodynamic limit. Therefore, the basic description

for nonintegrable quantum system is in terms of density matrices, and not of wave amplitudes.

In the kinetic theory, a long standing problem whether the kinetic equations exist in two

dimensional systems was solved. Kinetic equations exist for all dimensions. It was also shown

that the nonMarkovian effects, such as long-time tails, invalidate traditional kinetic theory based

on a truncation of the BBGKY hierarchy for reduced distribution functions, or on the Green-Kubo

formalism based on the decay of fluctuations.

Theoretical studies and numerical simulation of dynamical properties of ballistic electron

waveguides has begun. A direct connection between zeros in the electron conductance of these

devices and quasibound states related to geometric shape of the waveguides has been found.

Engineering Research 59 1997
University Of Texas At Austin

Dept of Physics $10,676

Austin, TX 78712

Complex Spatiotemporal Patterns in Nonequilibrium Systems

H. Swinney

The formation of time-dependent spatial patterns is being studied in chemical and physical

systems driven far from equilibrium. The goal is to understand what features of behavior are

common in diverse patter-forming systems. What kinds of patterns arise spontaneously as the

stress is increased on an initially homogeneous system? What kinds of transitions are permitted

between different patterns? What is the role of symmetries in the boundary conditions and the

equations of motion? These issues and their relation to applications are being addressed in

laboratory experiments, numerical simulations, and analyses on reaction-diffusion systems and

vertically vibrated granular media. Experiments on a periodically forced reaction-diffusion system

reveal a sequence of resonant regimes where the patterns oscillate at frequencies that are

rationally related to the forcing frequency. These frequency-locked regimes are analogous to the

frequency-locked tongues of a driven nonlinear pendulum, except that in the spatially expended

reactor, different frequencies correspond to different spatial patterns. Vibrated granular media

are being studied to determine the dependence of pattern wavelength on forcing frequency. The

dispersion relations obtained in experiments and simulations agree well and show two distinct

scaling regimes as the drive frequency is varied.

Tufts University

Department of Mechanical Engineering $124,303

Medford, MA 02155

Solids with Cracks and Pores of Various Shapes: Proper Parameters of Defect Density,

Anisotropy and Extraction of Information on Damage from Wavespeed Patterns

M. Kachanov

The work is motivated by a number of problems in materials science, geophysics and

poroelasticity related to the fact that real materials often contain defects whose shapes are

neither spherical nor crack-like, or mixtures of defects of diverse shapes (for example, pores and

microcracks). These shape factors strongly affect the effective response and anisotropy; their

neglection may lead to wrong interpretations of various experimental data on porous materials.

In particular, they are important for proper interpretation of anisotropic wavespeed patterns in

materials with cracks and pores and for the extraction of information on damage from such

patterns. Presently, a consistent unified treatment of these issues seems to be lacking. It will

be established what kind of information can/cannot be extracted from such a data. For example,

preliminary result indicate that the difference between spheres and randomly oriented "needles"

in principle cannot be detected by measurements of porosity and longwave speeds, whereas the

difference between the spherical and the oblate shapes can be detected.

Engineering Research 60 1997

Engineering Research 60 1997
U U

It is also important to identify the "signatures" of the fluid presence in wavespeed patterns

(particularly in the cases of anisotropy). A related phenomenon is the stress wave induced fluid

"pressure polarization", i.e. different fluid pressures in cavities (1) of different shapes, and (2)

differently oriented with respect to the wave induced stresses. This phenomenon is coupled with

the overall stiffness and, thus, with wavespeeds themselves.

The problems to be addressed fall into three categories:

- Prediction of the anisotropic effective response and wavespeeds in terms of information on

damage (damage elements of diverse shapes, possibly filled with compressible fluid) and fluid

compressibility.

- Inversely, recovery of all possible information on damage from the wavespeeds' data and

establishing the extent of certainty in the information recovery. Identification of "signatures" of

fluid presence in wavespeed patterns.

- Micromechanical interpretation of phenomenological constants in Biot's proelasticity theory.

University of Washington

Dept of Mechanical Engineering $73,412

Seattle, WA 98195

3-D Experimental Fracture Analysis at High Temperature II

A. Kobayashi

The objective of this three year project, which terminated on September 14, 1997, was to assess

experimentally, the validity of T* integral and its applicability to quasi-static and dynamic ductile

fracture. Early in the second year, a protocol for extracting the T* integral value from the

displacement field obtained by Moire interferometry was established. The procedure consisted

of numerically evaluating the integral along a partial contour at a small distance, e, in front of the

crack tip The e was equated to the plate thickness to ensure a state of plane stress and the

resultant T* was designated T*,. The procedure was verified through numerical experiments

conducted at the Georgia Institute of Technology (GIT) under a parallel DOE grant.

The established procedure was used to determine the T*e of 2024-T3 aluminum compact (CT)

specimens, 3.1 mm thick, with large crack growth of = 8 mm. T*, study of the A606 HSLA steel

specimens were discontinued due to the limited capacity of the available loading frame and the

excess plastic straining. T*, reached a steady state value of 140 MPa-mm with crack growth

and were within 5 percent of the T*E of 2024-T3 single edge notched (SEN) and central notched

(CN) specimens of 0.8 mm thickness. The crack tip opening angles (CTOA) immediately reached

a steady state value with crack growth without the crack tip blunting effect so noticeable in the

the thin SEN and CN specimens. The CT specimen results suggest that T*, and CTOA could be

viable fracture parameters which control stable crack growth.

Engineering Research 1997 Engineering Research 61997 61
Washington University

Department of Systems Science and Mathematics $92,906

Saint Louis, MO 63130

Visionics: An Integrated Approach to Analysis and Design of Intelligent Machines

B. Ghosh

Intelligent systems are systems capable of operating and performing satisfactorily in unknown

or partially known environment by learning about the structure and the shape of the ambient

where they operate, track the changes on line and adapt to the environment by changing

controller structure and goals. A typical motivation for this problem area is autonomous

navigation of vehicles and mobile or fixed robots operating in uncertain unknown and time

varying environments. For autonomous systems, many diverse subgoals of the mission must

in general be considered with the principal goal of the mission is to determine the control actions.

Our objective is to study 'Visually Guided Control Problems with specific applications to Vehicle

Navigation and Robotics. Primary effort in this proposal is to develop a unified and general set

of rational design criteria based on the paradigms of modem systems and control theory. The

autonomous guidance system will be adaptable to several kinds of scenarios and problems

where intelligent mobile navigation and navigating robots constitute a natural solution. The

following three subareas are currently being looked at.

1. Reconstructing 3D Motion and Shape of Moving Objects: This is an ongoing project where

spatio-temporal wavelet analysis is being used. The goal here is to obtain filters that are tuned

to a suitable orientation and velocity. The filters compute motion and shape parameters locally

in parallel.

2. Multisensor Guidance of Robot Manipulators in an Uncalibrated Environment: The goal

here is to guide a robot manipulator so as to track and grasp the position and orientation of an

object which is dynamically moving in the work-space of the robot. An important challenge here

is to recast the manipulation problem from the three dimensional task space to the 'sensor

space', that includes cameras and force/torque sensors. 'Sensor fusion' and 'Hybrid Control' are

the main focus of this project. Additionally, the problem of tracking a moving part has been

considered by introducing a new global 'parallel-tracking' scheme.

3. Autonomous Navigation of Mobile Robots: Goal here is to control a mobile vehicle armed

with multiple sensors that can navigate and perform "autonomous path planning", "estimate the

shape and motion of target objects" and is capable of tracking in order to keep objects in view.

Washington State University

Dept of Mech & Matis Engineering $0

Pullman, WA 99164-2920

Coupled Particle Dispersion by Three-Dimensional Vortex Structures

T. Troutt

The primary objective of this research program is to obtain understanding concerning the role

of three-dimensional vortex structures in the dispersion of particles and droplets in free shear

flows.

ngnerng R rh 62 1

Engineering Research 62 1997
This research builds on previous studies which focused on the nature of particle dispersion in

large scale quasi two-dimensional vortex structures which are a dominant component of free

shear flows. Although three dimensional vortex structures can be quite complex in nature, time

scaling quantities such as Stokes number can still be expected to be important for understanding

the particle dispersion process.

The study employs time-dependent experimental and numerical techniques to provide

,information concerning the particulate dispersion process produced by three-dimensional vortex

structures. The free shear flows investigated include perturbed plane mixing layers and wakes.

Three-dimensional two-phase flow simulation results indicate that streamwise vortex structures

can significantly alter the particle dispersion process in plane mixing layers.. The influence of

these streamwise structures appears to be most pronounced for particles with intermediate value

Stokes numbers. The development and nature of these streamwise vortices has also been

recently documented experimentally, providing comparison data for evaluating the numerical

results.

Additional experimental and numerical studies involving these new observations are presently

being pursued. Eventually insights from these three-dimensional particle dispersion results may

lead to improvements in the design of practical energy conversion systems.

University Of Wisconsin

Mechanical Engineering Dept $0

Milwaukee, WI 53201

Interfacial Area and Interfacial Transfer in Two-Phase Flow Systems

G. Kojasoy

The objectives of the proposed research program are to develop instrumentation methods, an

experimental data base, and an analysis leading to predictive models for describing the interfacial

structure and behaviors of horizontal two-phase flows. In terms of the flow structure, the

transverse distributions of the local void fraction, interfacial area concentration, fluid particle size

and their axial development from the entrance to the exit will be the primary focal point of the

research. For the purpose of understanding the dynamic behaviors, the interfacial velocity, wave

characteristics, fluid particle coalescence and disintegration will be studied. The axial changes

in the distribution of void fraction and interfacial area give the information on the particle

coalescence and disintegration. These will be characterized by the collision frequency and

interfacial energy and turbulence in the liquid.

A special emphasis will be placed on the further improvement of the multi-sensor resistivity probe

method which has been successfully developed and cross-calibrated against other global

techniques. The multi-sensor probes will be used together with hot-film probes for the liquid

turbulence measurements. These new measurements will give sufficient information to evaluate

the local relative velocity and momentum interaction between phases. Final focus of the

modeling effort is to develop interfacial area transport equation which incorporates the

mechanistic models for coalescence and disintegration of fluid particles. This transport equation

describes dynamical change of the interfacial structure and replaces the conventional model

based on flow regime transition criteria.

Engineering Research 63 1997
The proposed research program will provide: a) a new scientific instrumentation method for

studying detailed interfacial characteristics of two-phase flow, b) benchmark data for the local

interfacial area concentration, void fraction distribution, interfacial wave structure, relative

velocity and wave propagation velocity for horizontal two-phase flow systems, c) mechanistic

models for fluid particle coalescence and disintegration, and d) interfacial area transport

equation.

University Of Wisconsin

Dept of Chemical Engineering $119,900

Madison, WI 53706

New Process Modeling, Design and Control Strategies for Energy Efficiency,

High Product Quality, and Improved Productivity in the Process Industries

W. Ray

The process industries are having great difficulty competing in the world market because of high

energy costs, high labor rates, and old technology for many processes. This project is concerned

with the development of process design and control strategies for improving energy efficiency, product quality, and productivity in the process industry. In particular, (1) the resilient design and

control of chemical reactors, and (2) the operation of complex processing systems, will be

investigated. Major emphasis in part (1) will be on two important classes of chemical reactors:

polymerization processes and packed bed reactors. In part (2), the main focus will be on

developing process identification and control procedures which allow the design of advanced

control systems based on limited process information and which will work reliably when process

parameters change in an unknown manner. Specific topics to be studied include new process

identification procedures, nonlinear controller designs, adaptive control methods, and techniques

for distributed parameter systems. Both fundamental and immediately applicable results are

expected. The theoretical developments are being tested experimentally on pilot scale

equipment in the laboratory. These experiments not only allow improvements in theoretical work,

but also represent real life demonstrations of the effectiveness of the methods and of the

feasibility of implementing them in an industrial environment. The new techniques developed in

this project will be incorporated into computer-aided design packages and disseminated to

industry. Therefore, it is expected that the work will have an impact on industrial practice.

Engineering Research 64 1997

Engineering Research 64 1997
Principal Investigators

Investigator Paae No.

H..Abarbanel Phone: (619) 534-5590; Fax: (619) 534-7664; e-mail: hdia@hamilton.ucsd.edu ............ 7

J. Achenbach Phone: (847) 491-5527; Fax: (847) 491-5227; e-mail: achenbach@nwu.edu ............... 44

A. Acrivos Phone: (212) 650-8159; Fax: (212) 650-6835; e-mail: acrivos@scisun.sci.ccny.cuny.edu ..... 41

G. Ahlers Phone: (805) 893-3795; Fax: (805) 893-4170; e-mail: guenter@stc.ucsb.edu .............. 12

S. Altobelli Phone: (505) 262-7575; Fax: (505) 262-7043; e-mail: salto@nmr.org .................. 28

S. Atluri Phone: (310) 206-0942; Fax: (310) 267-1922; e-mail: atluri@seas.ucla.edu ........... ... 19

S. Banerjee Phone: (805) 893-3456; Fax: (805) 893-4731; e-mail: banerjee@anemone.ucsb.edu ........ 12

S. Bankoff Phone: (847) 491-5267; Fax: (847) 491-3728; e-mail: gbankoff@casbah.acns.nwu.edu ...... 44

J. Barhen Phone: (423) 574-7131; Fax: (423) 574-0405; e-mail: barhen@ornl.gov .................. 47

D. Barnett Phone: (650) 723-4143; Fax: (650) 725-4034; e-mail: barnett@leland.stanford.edu .......... 56

P. Barton Phone: (617) 253-6526; Fax: (617) 258-5042; e-mail: pib@mit.edu ...................... 32

T. Basar Phone: (217) 333-3607; Fax: (217) 244-1653; e-mail: tbasar@isaacs.csl.uiuc.edu .......... 23

R. Behringer Phone: (919) 660-2550; Fax: (919) 660-2525; e-mail: bob@physics.phy.duke.edu .......... 18

B. Berger Phone: (301) 405-5283; Fax: (301) 314-9477; e-mail: berger@eng.umd.edu ............... 29

P. Bernard Phone: (301) 405-5272; Fax: (301) 314-9477; e-mail: bernard@eng.umd.edu .............. 31

L. Biegler Phone: (412) 268-2232; Fax: (412) 268-7139; e-mail: biegler@cmu.edu .................. 14

H. Blanch Phone: (510) 642-1387; Fax: (510) 643-1228; e-mail: blanch@socrates.berkeley.edu ........ 3

I. Blankson Phone: (216) 433-5823; Fax: (216) 433-3000; e-mail: isaiah.m.blankson@lerc.nasa.gov ..... 39

H. Brenner Phone: (617) 253-6687; Fax: (617) 258-8224; e-mail: hbrenner@mit.edu ............ ..... 35

F. Brust Phone: (614) 424-5034; Fax: (614) 424-3457; e-mail: brust@em.battelle.org ............... 2

D. Cannell Phone: (805) 893-3150; Fax: (805) 893-4170; e-mail: david@alice.ucsb.edu ............. . 12

A. Caprihan Phone: (505) 262-7575; Fax: (505) 262-7043; e-mail: arvind@nmr.org ................... 28

I. Catton Phone: (310) 825-5320; Fax: (310) 206-4830; e-mail: catton@.ucla.edu ................. 6

E.G.D. Cohen Phone: (212) 327-8855: Fax: (212) 327-8507; e-mail: egdc@rockvax.rockefeller.edu ........ 54

S. Datta Phone: (303) 492-0287; Fax: (303) 492-3498; e-mail: dattas@spot.colorado.edu ........... 15

S. Davis Phone: (847) 491-5397; Fax: (847) 491-2178; e-mail: sdavis@casbah.acns.nwu.edu ........ 44

T. Eagar Phone: (617) 253-3229; Fax: (617) 252-1773; e-mail: tweagar@mit.edu .................. 32

J. Ekin Phone: (303) 497-5448; Fax: (303) 497-5316; e-mail: ekin@boulder.nist.gov .............. 40

J. Epstein Phone: (208) 526-6874; Fax: (208) 526-0690; e-mail: esj@inel.gov ...................... 21

L. Evans Phone: (617) 577-0100; Fax: (617) 577-0722; e-mail: evans@aspentec.com ............... 32

H. Fasel Phone: (520) 621-2771; Fax: (520) 621-8191; e-mail: faselh@ccit.arizona.edu ............. 1

J. Fincke Phone: (208) 526-2031; Fax: (208) 526-2814; e-mail: jf1@inel.gov ................. ... 19

L. Freund Phone: (401) 863-1476; Fax: (401) 863-1157; e-mail: freund@isaac.engin.brown.edu ....... 3

E. Fukushima Phone:.(505) 262-7575; Fax: (505) 262-7043; e-mail: eiichi@nmr.org .................... 28

H. Gao Phone: (650) 725-2560; Fax: (650) 723-1778; e-mail: gao@am-sun2.stanford.edu .......... 56

J. Georgiadis Phone: (217) 244-7578; Fax: (217) 333-1942; e-mail: georgia@staff.uiuc.edu .............. 18

B. Ghosh Phone: (314) 935-6039; Fax: (314) 935-6121; e-mail: ghosh@zach.wustl.edu .............. 62

R. Goldstein Phone: (612) 625-5552; Fax: (612) 625-3434; e-mail: rjgumn@mailbox.mail.umn.edu ....... 36

A. Graham Phone: (505) 665-5259; Fax: (505) 665-9521; e-mail: graham@lanl.gov .................. 35

C.P. Grigoropoulos Phone: (510) 642-2525; Fax: (510) 642-6163; e-mail: cgrigoro@euler.berkeley.edu ......... 4

I. Grossmann Phone: (412) 268-2230; Fax: (412) 268-7139; e-mail: grossmann@cmu.edu ............... 14

-HH
Principal Investigators (cont'd - pg. 2)

H.J.M. Hanley Phone: (303) 497-3320; Fax: (303) 497-5044; e-mail: hanley@central.bldrdoc.gov .......... 40

T. Hanratty Phone: (217) 333-1318; Fax: (217) 333-5052; e-mail: thanratt@uiuc.edu .................. 23

W. Haynes . Phone: (303) 497-3247; Fax: (303) 497-5044; e-mail: william.haynes@nist.gov ............. 41

J. Heberlein Phone: (612) 625-4538; Fax: (612) 624-1398; e-mail: jvrh@me.umn.edu .................. 36

J. Hickman Phone: (202) 994-3863; Fax: (202) 994-5873; e-mail: jhickman@gwu.edu ............... 55

J. Hunziker Phone: (202) 334-1571; Fax: (202) 334-2290; e-mail: jhunzike@nae.edu ................. 37

M. Ishii Phone: (765) 494-4587; Fax: (765) 494-9570; e-mail: grad@ecn.purdue.edu .............. 50

Y. Iwasa Phone: (617) 253-5548; Fax: (617) 253-5405; e-mail: iwasa@jokaku.pfc.mit.edu ........... 33

G: Johnson Phone: (919) 684-7754; Fax: (919) 684-7122; e-mail: gaj@orion.mc.duke.edu ............. 18

J. Johnson Phone: (208) 526-9021; Fax: (208) 526-0690; e-mail: jsq@inel.gov ...................... 20

D. Joseph Phone: (612) 625-0309; Fax: (612) 626-1558; e-mail: joseph@aem.umn.edu .............. 37

M. Kachanov Phone: (617) 627-3318; Fax: (617) 627-3819; e-mail: mkachano@tufts.edu ............... 60

A. Kaufman Phone: (510) 486-7899; Fax: (510) 486-4773; e-mail: ankaufman@lbl.gov ................ 27

R. Kayser Phone: (301) 975-2483; Fax: (301) 869-4020; e-mail: richard.kayser@nist.gov ............. 41

A. Kerstein Phone: (510) 294-2390; Fax: (510) 294-2595; e-mail: kerstein@ca.sandia.gov ............. 55

G. Kino Phone: (650) 723-0205; Fax: (650) 725-2533; e-mail: kino@macro.stanford.edu ............ 57

A. Kobayashi Phone: (206) 543-5488; Fax: (206) 685-8047; e-mail: ask@u.washington.edu .............. 61

G. Kojasoy Phone: (414) 229-5639; Fax: (414) 229-6958; e-mail: kojasoy@csd.uwm.edu .............. 63

R. Kraichnan Phone: (505) 986-3979; Fax: (505) 989-4737; e-mail: rhk@lanl.gov ...................... 26

E. Krempl Phone: (518) 276-6985; Fax: (518) 276-6025; e-mail: krempe@rpi.edu ................... 51

C. Kruger Phone: (650) 723-0977; Fax: (650) 725-1653; e-mail: kruger@soe.stanford.edu ........... 57

C. Law Phone: (609) 258-5271; Fax: (609) 258-6233; e-mail: cklaw@princeton.edu ............... 49

S.C. Li Phone: (619) 534-3168; Fax: (619) 534-6337; e-mail: scli@ames.ucsd.edu ................ 11

P. Libby Phone: (619) 534-3168; Fax: (619) 534-5354; e-mail: libby@ames.ucsd.edu ............... 11

K. Likharev Phone: (516) 632-8159; Fax: (516) 632-8774; e-mail: klikharev@ccmail.sunysb.edu ......... 43

K. Lindenberg Phone: (619) 534-3285; Fax: (619) 534-7244; e-mail: klindenberg@ucsd.edu .............. 8

R. Littlejohn Phone: (510) 486-7901; Fax: (510) 486-4773; e-mail: rglittlejohn@lbl.gov ................. 27

W: Lloyd Phone: (208) 526-1509; Fax: (208) 526-0690; e-mail: qrl@inel.gov ...................... 21

F. McClintock Phone: (617) 253-2219; Fax: (617) 258-8742 ................................ '... 33

M. McCready Phone: (219) 631-7146; Fax: (219) 631-8366; e-mail: mccready.1@nd.edu ................ 47

J. VcLaughlin Phone: (315) 268-6663; Fax: (315) 268-6654; e-mail: jmclau@sun.soe.clarkson.edu ........ 15

J. Mayergoyz Phone: (301) 405-3657; Fax: (301) 314-9281; e-mail: isaak@eng.umd.edu ................ 30

C. Menyuk Phone: (410) 455-3501; Fax: (410) 455-6500; e-mail: menyuk@umbc.edu ............... 30

M. Miksis Phone: (847) 491-5585: Fax: (847) 491-2178; e-mail: miksis@nwu.edu ................... 45

I. Minis Phone: (301) 405-5310: Fax: (301) 314-9477; e-mail: minis@eng.umd.edu ................ 29

L. Mondy Phone: (505) 844-1755; Fax: (505) 844-8251; e-mail: lamondy@sandia.gov ............... 35

F. Moon Phone: (607) 255-7146; Fax: (607) 255-1222; e-mail: fcm3@cornell.edu ............. 16

I. Mudawar Phone: (765) 494-5705; Fax: (765) 494-0539; e-mail: mudawar@ecn.purdue.edu ........... 51

S. Namachchivaya Phone: (217) 244-0683; Fax: (217) 244-0720; e-mail: sri@nsgsun.aae.uiuc.edu ............ 24

E. Novikov Phone: (619) 534-0816; Fax: (619) 534-7664; e-mail: enovikov@ucsd.edu ................ 8

R.J. Nunge Phone: (315) 268-6661; Fax: (315) 268-6654; e-mail: ................................ 15

1T'~~~~~~~~~~~
Principal Investigators (cont'd - pg. 3)

E. Oblow Phone: (423) 574-6187; Fax: (423) 574-7860; e-mail: oblowem@ornl.gov ................. 47

L. Ong Phone: (301) 405-5343; Fax: (301) 314-9477; e-mail: lawrence@eng.umd.edu ............. 31

A. Ortega Phone: (520) 621-6787; Fax: (520) 621-8191; e-mail: ortega@ccit.arizona.edu ............. 1

J. Ottino Phone: (847) 491-3558; Fax: (847) 491-3728; e-mail: ottino@chem-eng.nwu.edu ........... 45

T. Owano Phone: (650) 723-1295; Fax: (650) 723-1748; e-mail: owano@saha.stanford.edu ........... 57

L. Parker Phone: (423) 241-4959; Fax: (423) 574-7860; e-mail: parkerle@ornl.gov .................. 47

D. Parks Phone: (617) 253-0033; Fax: (617) 258-8742 ...................... ................. 33

T. Petrosky Phone: (512) 471-7253; Fax: (512) 471-9621; e-mail: petrosky@physics.utexas.edu ......... 59

J. Plawsky Phone: (518) 276-6049; Fax: (518) 276-4030; e-mail: plawsky@rpi.edu ................... 52

I. Prigogine Phone: (512) 471-7253; Fax: (512) 471-9621; e-mail: annie@physics.utexas.edu .......... 59

A. Prosperetti Phone: (410) 516-8534; Fax: (410) 516-7254; e-mail: prosper@titan.me.jhu.edu ............ 26

V. Protopopescu Phone: (423) 574-4722; Fax: (423) 574-0405; e-mail: protopopesva@ornl.gov ............. 47

S. Putterman Phone: (310) 825-2269; Fax: (310) 206-5668; e-mail: putterman@physics.ucla.edu ......... 7

M. Rabinovich Phone: (619) 534-0816; Fax: (619) 534-7664; e-mail: lev@gibbs.ucsd.edu ................ 9

E. Rabinowicz Phone: (617)253-2230 . ................... ........................... 33

N.S.V. Rao Phone: (423) 574-7517; Fax: (423) 574-7860; e-mail: raons@ornl.gov ................... 47

W. Ray Phone: (608) 263-4732; Fax: (608) 262-0832; e-mail: ray@engr.wisc.edu ................. 64

D. Reister Phone: (423) 574-2272; Fax: (423) 574-7860; e-mail: dbr@ornl.gov ..................... 47

W. Reuter Phone: (208) 526-1708; Fax: (208) 526-0690; e-mail: wgr2@inel.gov ................... 21

L. Riechl Phone: (512) 471-7253; Fax: (512) 471-9621; e-mail: reichl@physics.utexas.edu ........... 59

H. Riecke Phone: (847) 491-3345; Fax: (847) 491-2178; e-mail: h-riecke@nwu.edu ................. 46

I. Rinard Phone: (212) 650-7135; Fax: (212) 650-6686; e-mail: rinard@che-mail.engr.ccny.cuny.edu ... 42

A. Rosakis Phone: (818) 395-4523; Fax: (818) 304-0175; e-mail: rosakis@atlantis.caltech.edu ......... 13

J. Ross Phone: (650) 723-9203; Fax: (650) 723-4817; e-mail: ross@chemistry.stanford.edu ......... 58

T. Rozzell Phone: (202) 334-2908; Fax: (202) 334-3419; e-mail: trozzell@nas.edu .................. 38

H. Sehitoglu Phone: (217) 333-4112; Fax: (217) 244-6534; e-mail: huseyin@ux1.cso.uiuc.edu ........... 25

G. Settles Phone: (814) 863-1504; Fax: (814) 865-0118; e-mail: gss2@psu.edu ................... 49

J. Sheridan Phone: (313) 995-4963; Fax: (313) 995-1150; e-mail: johns@ncms.org ................... 39

R. Shinnar Phone: (212) 650-6679; Fax: (212) 650-6686; e-mail: shinnar@che-mail.engr.ccny.cuny.edu .. 42

G. Sivashinsky Phone: (212) 650-8157; Fax: (212) 650-6835; e-mail: chemw@ccnyvme ................. 42

H. Smartt Phone: (208) 526-8333; Fax: (208) 526-0690; e-mail: hbs@inel.gov ..................... 21

R. Spanos Phone: (713) 527-4909; Fax: (713) 285-5191; e-mail: spanos@rice.edu .................. 53

G. Stephanopoulos Phone: (617) 253-4583; Fax: (617) 253-3122; e-mail: gregstep@mit.edu .................. 34

D. Stoner Phone: (208) 526-8786; Fax: (208) 526-0828; e-mail: dls2@inel.gov .................... 20

C. Surko Phone: (619) 534-6880; Fax: (619) 534-0173; e-mail: csurko@ucsd.edu .................. 10

H. Swinney Phone: (512) 471-4619; Fax: (512) 471-1558; e-mail: swinney@chaos.ph.utexas.edu ........ 60

S. Teitel Phone: (716) 275-4039; Fax: (716) 275-8527; e-mail: stte@pas.rochester.edu ............. 53

K. Telschow Phone: (208) 526-1264; Fax: (208) 526-0690; e-mail: telsch@inel.gov .................... 22

C. Tien Phone: (510) 643-3886; Fax: (510) 643-3887; e-mail: nancie@uclink4.berkeley.edu ......... 4

S. Torquato Phone: (609) 258-3341; Fax: (609) 258-2685; e-mail: torquato@matter.princeton.edu ....... 50

T. Troutt Phone: (509) 335-4375; Fax: (509) 335-4662; e-mail: troutt@mme.wsu.edu .............. 62

L. Tsimring Phone: (619) 534-0816; Fax: (619) 534-7664; e-mail: lev@gibbs.ucsd.edu ................ 10

* U_____
Principal Investigators (cont'd - pg. 4)

W.A. Van Der Sluys Phone: (330) 829-7456; Fax: (330) 829-7832; e-mail: alan.w.vandersluys@mcdermott.com ... 29

J. Vinals Phone: (904) 644-1010; Fax: (904) 644-0098; e-mail: vinals@scri.fsu.edu ................. 18

J. Wallace Phone: (301) 405-5271; Fax: (301) 314-9477; e-mail: wallace@eng.umd.edu ............. 31

G. Wallis Phone: (603) 646-2789; Fax: (603) 646-3856; e-mail: graham.b.wallis@dartmouth.edu ...... 17

Z. Warhaft Phone: (607) 255-3898; Fax: (607) 255-1222; e-mail: zw16cornell.edu ................. 17

P.C. Wayner Phone: (518) 276-6199; Fax: (518) 276-4030; e-mail: wayner@rpi.edu ................... 52

J.R. Welty Phone: (541) 737-4902; Fax: (541) 737-2600; e-mail: weltyj@ccmail.orst.edu ............. 48

A. Westerberg Phone: (412) 268-2344; Fax: (412) 268-7139; e-mail: a.westerberg@cmu.edu ............. 14

G. Wilemski Phone: (573) 341-4409; Fax: (573) 341-4891; e-mail: wilemski@umr.edu ................. 27

.F. Williams Phone: (619) 534-5492; Fax: (619) 534-5354; e-mail: faw@ames.ucsd.edu ............... 11

R. Winston Phone: (312) 702-7756; Fax: (312) 702-6317; e-mail: winston@rainbow.uchicago.edu ....... 14

E. Wolf Phone: (716) 275-4397: Fax: (716) 473-0687 ....................................... 54

I. Wygnanski Phone: (520) 621-6089; Fax: (520) 621-8191; e-mail: wygy@bigdog.engr.arizona.edu ....... 1

Y. Xu Phone:' (303) 497-7894; Fax: (303) 497-5316; e-mail: yizixu@boulder.nist.gov ............. 40

R. Zare Phone: (650) 723-3062; Fax: (650) 723-9262; e-mail: zare@stanford.edu ................. 59

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